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MerCruiser GM4 Service Manual

Gm 4 cylinder
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MARINE ENGINES

GM 4 Cylinder
1995, Brunswick Corporation
Printed in U.S.A.
90-816462 2-695

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Summary of Contents for MerCruiser GM4

  • Page 1: Marine Engines

    MAIN MENU MARINE ENGINES GM 4 Cylinder 1995, Brunswick Corporation Printed in U.S.A. 90-816462 2-695...
  • Page 2 90-816462 2-695...
  • Page 3 Notice We could not possibly know of and advise the service trade of all conceivable procedures by which a ser- Throughout this publication, “Dangers,” “Warnings” vice might be performed and of the possible hazards and “Cautions” are used to alert the mechanic to spe- and/or results of each method.
  • Page 4 Unlike automotive Electrical, ignition and fuel system components engines, marine engines are subjected to extended on MerCruiser Engines and Stern Drives are de- periods of heavy load and wide-open-throttle opera- signed and manufactured to comply with U.S.
  • Page 5 Models Covered In This Manual MODEL SERIAL NUMBER MCM 3.0L OC856451 And Above MCM 3.0L /3.0LX OC868143 And Above IMPORTANT: Refer To ”Engine Identification”, Page 3A-7 NOTICE Refer To Appropriate Stern Drive Manual fof transom assembly and stern drive unit repair. 90-816462 2-695...
  • Page 6 Service Manual Outline SECTION 1 - Important Information A - General Information B - Maintenance C - Troubleshooting SECTION 2 - Removal and Installation A - 4 Cylinder 3.0L / 3.0 LX (181 C.I.D.) SECTION 3 - Engine A - G.M. In-Line SECTION 4 - Electrical Systems A - Starting System B - Ignition System...
  • Page 7 IMPORTANT INFORMATION 72000 GENERAL INFORMATION Index...

  • Page 8: Table Of Contents

    Table of Contents Page Page Introduction ......1A - 1 Boat And Engine Performance .

  • Page 9: Introduction

    Introduction How to Use This Manual This comprehensive overhaul and repair manual is This manual is divided into sections which represent designed as a service guide for the models previously major components and systems. listed. It provides specific information, including pro- Some sections are further divided into parts which cedures for disassembly, inspection, assembly and more fully describe the component.

  • Page 10: How To Read Parts Manual

    How To Read Parts Manual 26790 CYLINDER BLOCK AND CAMSHAFT REF. PART NO. DESCRIPTION QUAN. 841-824146 CYLINDER BLOCK (See Note) 19-34270 EXPANSION PLUG 17-35465 DOWEL PIN 22-72640 EXPANSION PLUG 23-85674 BEARING UNIT (SET) 22-48556 BUSHING 22-32802 PIPE PLUG 22-42796 BY-PASS VALVE 19-816565 PLUG 811844...

  • Page 11: Directional References

    Directional References Engine Serial Number Locations Front of boat is bow; rear is stern. Starboard side is right side; port side is left side. In this maintenance manual, all directional references are given as they appear when viewing boat from stern looking toward bow.

  • Page 12: Water Testing New Engines

    For best speed and minimum spray, the corner be- Use care during the first 20 hours of operation on new tween the bottom and the transom should be MerCruiser engines or possible engine failure may sharp. occur. If a new engine has to be water-tested at full throttle before the break-in period is complete, follow this procedure.

  • Page 13: Marine Fouling

    72004 Avoid corrosion damage. Do not apply antifouling a - Hook paint to MerCruiser drive unit or transom assembly. IMPORTANT: If antifouling protection is required, Tri-Butyl-Tin-Adipate (TBTA) base antifouling A “rocker” is the reverse of a hook. The bottom is con- paints are recommended on MerCruiser boating vex or bulged in the fore-and-aft direction.

  • Page 14: Weight Distribution

    Weight Distribution Elevation and Climate Weight distribution is extremely important; it affects a Elevation has a very noticeable effect on the wide- boat’s running angle or attitude. For best top speed, open-throttle power of an engine. Since air (contain- all movable weight - cargo and passengers - should ing oxygen) gets thinner as elevation increases, the be as far aft as possible to allow the bow to come up engine begins to starve for air.
  • Page 15 IMPORTANT INFORMATION 50617 MAINTENANCE Index...
  • Page 16 Table of Contents Page Page Checking Engine Oil Level/Filling ..1B - 9 Maintenance Schedule ....1B - 1 Changing Oil and Filter .

  • Page 17: Maintenance Schedule

    Maintenance Schedule Always disconnect battery cables from battery BEFORE working around electrical system components to prevent injury to yourself and damage to electrical system should a wire be accidentally shorted. To Be Done by Owner TASK INTERVAL Cooling System - Flush seawater section Saltwater: After each use Seawater strainer Clean as required...

  • Page 18: Maintenance Schedule (Continued)

    Maintenance Schedule (Continued) To Be Done by Dealer TASK INTERVAL 20–Hour checkup (NOTE 1) 20 hours Whenever insufficient seawater flow is Seawater pickup pump - disassemble and inspect suspected. (if operating temperature exceeds normal range) Flame arrestor and crankcase ventilation hose - clean and inspect Stern drive unit oil - change Gimbal ring clamping screws - retorque to 40 lb.

  • Page 19: Tune-Up Specifications

    Tune-Up Specifications Model MCM 3.0L MCM 3.0LX Propshaft Horsepower Ratings 115 (86) 135 (101) (Kilowatts) Number Of Cylinders Displacement 181 CID (3.0L) Bore/Stroke 4.00 in./3.60 in. (101.6/91.4 mm) Compression Ratio 9.25:1 Compression Pressure 140 PSI (966 kPa) Idle RPM (in Forward Gear) 650-700 Maximum RPM (at W.O.T.) 4200-4600...

  • Page 20: Fluid Capacities

    Fluid Capacities NOTICE All capacities are approximate fluid measures. MCM (Stern Drive) Model All Models Crankcase Oil (with filter) 4 U.S. Qts. (3.8 L) Seawater Cooling System 9 U.S. Qts. (3.8 L) Closed Cooling System 9 U.S. Qts. (8.5 L) Always use dipstick to determine exact quantity of oil required Seawater cooling system capacity information is for winterization use only Index...

  • Page 21: Cylinder

    After 20 Hour Break-In Period Retorque gimbal ring clamping U-bolt to 55 lb. ft. (74 N·m). To help extend the life of your MerCruiser power package, the following recommendations should be considered: Use a propeller that allows the engine to operate at...

  • Page 22: Fuel, Oil, Fluid, And Coolant Specifications

    The adverse effects of alcohol are more severe with engine and is not covered under MerCruiser War- methyl alcohol (methanol) and are worse with in- ranty.

  • Page 23: Gasoline/Alcohol Blends

    ETHANOL. Alcohol is also more severe in older en- age resulting from the use of gasoline-alcohol gines since newer engines have materials which are blended fuels are not the responsibility of MerCruiser more resistant to alcohol. and will not be covered under our warranty.

  • Page 24: Crankcase Oil

    Crankcase Oil Tools Required To help obtain optimum engine performance and to provide maximum protection, we strongly recom- mend the use of Quicksilver 4-Cycle Marine Engine Oil. If not available, a good grade, straight weight, de- tergent automotive oil of correct viscosity, with an API classification of SF or SG, may be used.

  • Page 25: Coolant For Closed Cooling System

    6. Remove oil filler cap from valve rocker arm cover. arm “clatter” on MerCruiser engines. The over-full 7. Add required amount of oil to bring level up to, but condition results in the engine crankshaft splashing not over, the FULL mark on dipstick.

  • Page 26: Maintaining Power Steering Pump Fluid Level

    6. Coat sealing ring on new filter with engine oil, and 3. Level should be between the FULL HOT mark install. Tighten filter securely (following filter man- and ADD mark on dipstick. ufacturer’s instructions). Do not over-tighten. 72518 a - Proper Fluid Level with Engine Warm 4.

  • Page 27: Filling And Bleeding Power Steering System

    Filling and Bleeding Power Maintaining Closed Cooling Steering System Coolant Level WARNING IMPORTANT: Power steering system must be Allow engine to cool down before removing pres- filled exactly as explained in the following to be sure cap. Sudden loss of pressure could cause sure that all air is bled from the system.
  • Page 28 WARNING CAUTION When flushing cooling system with boat out of If cooling system is to be flushed with boat in the the water, be certain that area in vicinity of propel- water, seacock (if so equipped) must be closed, ler is clear and that no person is standing nearby. or water inlet hose must be disconnected and As a precautionary measure, it is recommended plugged to prevent water from flowing into boat.

  • Page 29: Lubrication

    Lubrication CAUTION Watch temperature gauge at dash to ensure the Lubricate pivot points with SAE 30W motor oil and engine does not overheat. cable guide contact surfaces with Quicksilver 2-4-C Marine Lubricant with Teflon. 4. Operate engine at idle speed in NEUTRAL gear for 10 minutes or until discharge water is clear, Throttle Cable then stop engine.

  • Page 30: Engine Coupler/U-Joint Shaft Splines

    NOTE: Refer to MerCruiser Stern Drive Service Man- ual for stern drive unit removal and installation if nec- Fresh Water Areas - Every 50 Hours of operation essary.

  • Page 31: Layup

    CAUTION CAUTION Seawater section of cooling system MUST BE A discharged battery can be damaged by freez- COMPLETELY drained for winter storage, or im- ing. mediately after cold weather use, if the possibility of freezing temperatures exists. Failure to com- Layup ply may result in trapped water causing freeze and/or corrosion damage to engine.

  • Page 32: Draining Instructions

    13. Clean outside of engine and repaint any areas re- 3. Repeatedly clean out drain holes using a stiff quired with Quicksilver Primer and Spray Paint. piece of wire. Do this until entire system is After paint has dried, spray Quicksilver Corrosion drained.
  • Page 33 If NOT equipped with sea- cock: seawater inlet hose must remain discon- nected and plugged until engine is to be restarted. IMPORTANT: MerCruiser recommends that pro- pylene glycol antifreeze (nontoxic and biode- gradable, which makes it friendly to lakes and riv- ers) be used in sea-water section of the cooling system for cold weather or extended storage.

  • Page 34: Draining Seawater Section Of Closed Cooled (Coolant) Models

    Draining Seawater Section of Closed 5. If equipped with 3 in. (76 mm) or 6 in. (152 mm) risers, remove drain plug as shown from riser. Cooled (Coolant) Models NOTICE Refer to “Cold Weather or Extended Storage,” “Precautions,” in this section, BEFORE proceeding.

  • Page 35: Recommissioning

    8. Insert a small wire (repeatedly) to make sure that 10. After seawater section of cooling system has vent holes and water drain holes and passages been drained completely, coat threads of drain (as shown) are unobstructed and open. plugs with Quicksilver Perfect Seal and reinstall. Tighten drain plugs securely.
  • Page 36 IMPORTANT INFORMATION TROUBLESHOOTING Index...
  • Page 37 Table of Contents Page Page Carburetor Malfunction ....1C- 15 Precautions ......1C- 1 Engine Runs Poorly At Idle .

  • Page 38: Precautions

    Precautions CAUTION DO NOT operate engine without cooling water be- ing supplied to water pickup holes in gear hous- WARNING ing, or water pump impeller will be damaged and Always disconnect battery cables from battery subsequent overheating damage may result. BEFORE working on fuel system to prevent fire or explosion.

  • Page 39: Used Spark Plug Analysis

    Used Spark Plug Analysis Chipped Insulator Chipped insulator usually results from careless plug Use the following illustrations for determining ser- re-gapping. Under certain conditions, severe deto- viceability of spark plug. Spark plug condition also nation also can split insulator firing ends. Plug must can suggest a variety of possible engine malfunc- be replaced.

  • Page 40: Cold Fouling

    Cold Fouling High Speed Glazing Dry, black deposits indicate rich fuel mixture or Insulator has yellowish, varnish-like color, indicating weak ignition. Clogged flame arrestor, flooding car- that temperatures suddenly have risen, usually dur- buretor, sticky choke or weak ignition components ing hard, fast acceleration under heavy load.

  • Page 41: Pre-Ignition Damage

    Pre-Ignition Damage Splashed Deposits Pre-ignition damage is caused by excessive high Spotted deposits, which sometimes occur after long temperatures. Center electrode melts first, followed delayed tune-up, accumulate after a long period of by ground electrode. Normally, insulators are white misfiring. When normal combustion temperatures but may be dirty if plug has been misfiring.

  • Page 42: Poor Boat Performance And/Or Poor Maneuverability

    Poor Boat Performance and/or Poor Maneuverability Symptom Cause 1. Bow too low 1. A. Improper drive unit trim angle B. Improper weight distribution C. Boat is underpowered D. Permanent or power hook in boat bottom E. False bottom full of water F.

  • Page 43: Improper Full Throttle Engine Rpm

    Improper Full Throttle Engine RPM RPM Too High Cause Special Information 1. Propeller 1. Damaged; pitch too low; diameter too small; propeller hub slipping. 2. Boat 2. Water pickup or thru hull fittings mounted too close to propeller (ventilation); keel located too close to propeller and/or too deep in the water (ventilation).

  • Page 44: Engine Cranks Over But Will Not Start Or Is Hard To Start

    Engine Cranks Over But Will Not Start Or Is Hard To Start Important Information 3. Check ignition system operation. Remove coil 1. First, determine which engine system is causing wire from tower on distributor cap. Hold coil wire the problem. To make an engine run, basic com- near ground and check for spark while cranking ponents fuel, spark (ignition), and compression engine over.

  • Page 45: Digital Distributorless Ignition System (Ddis)

    Digital Distributorless Ignition System (DDIS) THE ENGINE FAILS TO START. Is spark normal? Is the spark plug normal? Replace the spark plug. Parts other than the DDIS are defective. Is spark plug wire good? Replace spark plug wire. The engine harness, battery Is the ignition amplifier power Is the engine harness ignition key, ignition amplifier...
  • Page 46 THE ENGINE FAILS TO IDLE. Is spark normal? Is the spark plug normal? Replace the spark plug. Parts other than the DDIS are defective. Is spark plug wire good? Replace spark plug wire. Is the ignition coil normal? (Check the primary and Replace the ignition secondary resistor insulation coil.

  • Page 47: Est Ignition System Check

    (“C”) PICK-UP B R E COIL IGNITION COIL CONNECTOR DISTRIBUTOR 3 TERMINAL CONNECTOR DISTRIBUTOR HEI MODULE DISTRIBUTOR IGN COIL FILTER CONN 71572 EST Ignition System Check Test Description 5. Applying a voltage (1.5 to 8 volts) to module termi- nal “P” should turn the module “ON” and the “tach” Numbers below refer to circled numbers on the terminal voltage should drop to about 7-9 volts.
  • Page 48 Ignition System Check(1 of 2) IF A TACHOMETER IS CONNECTED TO THE TACH TERMINAL, DISCONNECT IT BEFORE PROCEEDING WITH THE TEST. CHECK SPARK AT PLUG WIRE USING AN INDUCTIVE PICKUP TIMING LIGHT WHILE CRANKING. A FLASHING LIGHT INDICATES SPARK. (IF NO SPARK ON FIRST WIRE, CHECK SECOND WIRE.) A FEW SPARKS AND THEN NOTHING IS CONSIDERED NO SPARK.
  • Page 49 Ignition System Check (2 of 2) TEST LIGHT TO DC POWER SUPPLY (1.5 to 8 V) CHART CONTINUED FROM PREVIOUS PAGE LIGHT LIGHT ON BLINKS STEADY Fig. 1 DISCONNECT DISTRIBUTOR 4 TERMINAL CONNECTOR. REPLACE IGNITION COIL REMOVE DISTRIBUTOR CAP. AND RECHECK DISCONNECT PICK-UP COIL CONNECTOR FROM MODULE.

  • Page 50: Engine Will Not Crank Over/Starter Inoperative

    Engine Will Not Crank Over/Starter Inoperative Cause Special Information 1. Remote control lever not in neutral position 2. Battery charge low; damaged wiring; loose electrical connections 3. Circuit breaker tripped 4. Blown fuse 5. Ignition switch 6. Slave solenoid 7. Faulty neutral start safety switch 7.

  • Page 51: Noisy Alternator

    Noisy Alternator Cause Special Information 1. Loose mounting bolts 2. Drive belt 2. Worn, frayed, loose 3. Loose drive pulley 4. Worn or dirty bearings 5. Faulty diode trio or stator Fuel System Rich Cause Special Information 1. Warm engine carburetor percolation 1.

  • Page 52: Fuel System Lean

    Fuel System Lean Special Information Cause 1. Empty fuel tank 2. Fuel shut-off valve closed (if equipped) 3. Vapor lock 3. Engine will not start after warm engine shut down 4. Automatic choke 4. Stuck open, wrong adjustment 5. Fuel tank vent plugged 5.

  • Page 53: Engine Runs Poorly At Idle

    Carburetor Malfunction (continued) F. Throttle body heat passages plugged G. Main metering jets H. Float adjustment Secondary air valve wind-up 4. Engine surges 4. A. Main metering jets B. Leaking gaskets C. Float adjustment D. Saturated float E. Power piston or valve F.
  • Page 54 Engine Runs Poorly At Idle (continued) D. Incorrect float level drop E. If carburetor (2 bbl. only) has a solid needle, replace with a spring loaded needle 4. Moisture on ignition components 4. Cap or spark plug wires arcing 5. Water in fuel 6.

  • Page 55: Engine Acceleration Is Poor

    Engine Acceleration Is Poor Cause Special Instructions 1. Also refer to “Poor Boat Performance” 2. Idle mixture screws 3. Incorrect ignition timing 4. Incorrect distributor or amplifier advance curve 4. Refer to Section 4B 5. Accelerator pump 5. Check for stream of raw fuel from accelerator pump discharge nozzle, when opening throttle with engine shut off 6.

  • Page 56: Engine Runs Poorly At High Rpm

    Engine Runs Poorly At High RPM Cause Special Information 1. Also refer to “Poor Boat Performance” 2. Crankcase overfilled with oil 2. Check oil level with boat at rest in the water. 3. Anti-siphon valve (if equipped) 3. Restricting fuel supply 4.

  • Page 57: Poor Fuel Economy

    Poor Fuel Economy Cause Special Information 1. Fuel leaks 2. Operator habits 2. Prolonged idling; slow acceleration; failure to cut back on throttle once boat is on plane; boat over loaded; uneven weight distribution 3. Engine laboring 3. Bent, damaged, or wrong propeller. Water test boat for proper operating RPM at wide open throttle 4.

  • Page 58: Radio Noise

    Radio Noise Cause Special Information 1. A “popping” noise that will increase with engine 1. Ignition System - wrong spark plugs; cracked dis- RPM. Noise will stop as soon as engine is tributor cap; cracked coil tower; leaking spark turned off. plug wires;...

  • Page 59: Miscellaneous

    Miscellaneous Cause Special Information 1. Low grade or stale fuel 2. Water in fuel Instrumentation Malfunction Cause Special Information 1. Faulty wiring, loose or corroded terminals 2. Faulty key switch 2. Test, as outlined in SECTION 4D 3. Faulty gauge 3.

  • Page 60: Engine Noise

    Engine Noise 4. Try to isolate the noise to location in engine: front to back, top to bottom. This can help determine Important Information which components are at fault. No definite rule or test will positively determine 5. Sometimes noises can be caused by moving source of engine noise;...

  • Page 61: Camshaft Area

    Camshaft Area Location Possible Causes 1. Camshaft area, front of engine, timed to one half 1. A. Crankshaft timing sprocket engine speed B. Timing chain C. Fuel Pump D. Valve Lifter E. Cam Bearings 2. Camshaft area, center of engine, timed to one 2.

  • Page 62: Crankshaft Area

    Crankshaft Area Location Possible Causes 1. Crankshaft area, front of engine, timed to engine 1. A. Crankshaft timing sprocket speed B. Timing chain C. Main bearing D. Rod bearing 2. Crankshaft area, center of engine, timed to 2. A. Crankshaft striking pan or pan baffle engine speed B.

  • Page 63: Miscellaneous

    Miscellaneous Noise Possible Cause 1. Engine spark knock 1. A. Advanced timing B. Low octane fuel C. Engine running hot D. Carbon deposits in engine 2. Popping through carburetor 2. A. Wrong ignition timing B. Carburetor set too lean C. Faulty accelerator pump D.

  • Page 64: Oil Pressure

    Oil Pressure 1. Measuring oil pressure 1. Use a good automotive oil pressure test gauge. Do not rely on the oil pressure gauge in the boat. 2. Check engine oil level with boat at rest in the 2. Oil level should be between the ADD and FULL water marks 3.

  • Page 65: Low Oil Pressure

    Low Oil Pressure Cause Special Information 1. Low oil level in crankcase 2. Defective oil pressure gauge and/or sender 2. Verify with an automotive test gauge. Refer to SECTION 4D for instrument testing. 3. Thin or diluted oil 3. Oil broken down; contains water or gas; wrong viscosity;...

  • Page 66: Excessive Oil Consumption

    Excessive Oil Consumption Cause Special Information 1. Normal consumption. 1. One quart of oil consumed in 5-15 hours of opera- tion at wide-open-throttle (especially in a new or rebuilt engine) is normal 2. Oil leaks 2. Clean bilge, run engine with clean white paper on bilge floor, locate oil leak(s) 3.

  • Page 67: Water In Engine

    Water in Engine If water is contained to cylinder(s) only, it is usually entering through the intake system, exhaust sys- tem, or head gasket. Important Information If the water is contained to crankcase only, it is usu- ally caused by a cracked or porous block, a flooded IMPORTANT: First determine location of water in bilge, or condensation.

  • Page 68: Water On Top Pistons

    Water On Top Of Pistons Cause Special Information 1. Operator shut engine off at high RPM 2. Engine “diesels” or tries to run backwards 2. Engine out of tune, poor fuel, high idle RPM, timing set too high 3. Rain water running into flame arrestor 3.

  • Page 69: Engine Overheats (Mechanical)

    Engine Overheats (Mechanical) Cause Special Information 1. Engine RPM below specifications at wide- 1. Damaged or wrong propeller; growth on boat bot- open-throttle (engine laboring) tom;false bottom full of water 2. Wrong ignition timing 2. Timing too far advanced or retarded 3.

  • Page 70: Engine Overheats (Cooling System)

    Engine Overheats (Cooling System) Cause Special Information IMPORTANT: IMPORTANT: Best way to test gauge or sender is The first step is to verify if the engine is to replace them. actually overheating or the temperature gauge or sender is faulty 1.

  • Page 71: Poor, Erratic, Or No Assist

    Engine Overheats (Cooling System) (Continued) 15. Antifreeze not mixed properly 15. Antifreeze should be mixed 50/50 or maximum 60/40 (60% antifreeze, 40% water) 16. Heat exchanger cores plugged 17. Water hoses reversed at the water distribution 17. Refer to water flow diagram in SECTION 6 block Poor, Erratic, or No Assist Cause...

  • Page 72: Noisy Pump

    Noisy Pump Cause Special Information Drive belt 1. Check belt tension 2. Low fluid level 3. Air in fluid 3. Air leak in lines, pump, or air form installation 4. Faulty pump 4. Use stethoscope to listen for noise in pump 5.

  • Page 73: Insufficient Water Flow From Alpha One Stern Drive Unit Seawater Pickup Pump

    Insufficient Water Flow from Alpha One Stern Drive Unit Seawater Pickup Pump CAUSE SPECIAL INFORMATION Seawater shutoff valve partially or fully closed (if equipped) 2. Water pick up clogged with foreign material 3. Kinked or broken bell housing to gimbal housing water tube hose 4.

  • Page 74: Removal And Installation

    REMOVAL AND INSTALLATION 50633 4 CYL – ALPHA ONE DRIVE Index...
  • Page 75 Table of Contents Page Torque Specifications ..... 2A-1 Tools/Lubricants/Adhesives/Sealants ..2A-1 Removal ....... . 2A-2 Engine Removal .

  • Page 76: Torque Specifications

    Torque Specifications Tools/Lubricants/Adhesives/ Sealants DESCRIPTION Lb. In. Lb. Ft. Power Steering Hydrau- Description Part Number 20-25 27-34 lic Hose Fittings Quicksilver Engine 92-816391A4 Front Engine Mounts 30-40 42-54 Coupler Spline Grease Rear Engine Mounts 35-40 47-54 Quicksilver 2-4-C 92-825407A3 Marine Lubricant With Teflon Tighten Until Bottoms Drive Unit Shift Cables Out, Then Back Off 1/2...

  • Page 77: Engine Removal

    Removal IMPORTANT: Stern drive unit must be removed prior to engine removal. Refer to Stern Drive Ser- vice Manual. Engine Removal 1. Disconnect battery cables from battery. 50738 a - Fuel Pump b - Disconnect Fuel Inlet Line Here - Plug inlet hose 4.
  • Page 78 5. Disconnect shift cables and shift assist assembly 7. Loosen clamp and unplug wiring harness (if equipped). 50113 Breaker Point Ignition 50626 a - Locking Nut b – Shift Cable End c - Cotter Pin d - Shift Assist Assembly e - Clevis Pin (w/Cotter Pin) 6.
  • Page 79 8. Disconnect bullet connectors of trim sender wires 12. Loosen hose clamps and disconnect exhaust el- (coming from transom assembly) from engine bow hose. harness. 13. Remove both shift cables from shift plate. Retain NOTE: After wires are disconnected be sure to loos- locknuts and hardware.
  • Page 80 16. Support engine with suitable sling through lifting Installation eyes on engine and remove front and rear engine mounting bolts. Retain hardware. Engine Installation/Alignment 1. Follow instructions “a”-“e”: a. Be certain fiber washers (cemented in place) on inner transom plate are present. Inspect fi- ber washers.
  • Page 81 4. Align rear engine mounts with inner transom plate CAUTION mounts while simultaneously aligning exhaust Center lifting eye (located on top of thermostat tubes with exhaust pipe hoses (bellows). housing) is used for engine alignment only. DO NOT use to lift entire engine. CAUTION DO NOT allow lifting sling to hook or compress engine components or damage will occur.
  • Page 82 b. While observing the above precautions, CAUTION CAREFULLY raise and lower front of engine When lowering engine into position DO NOT set with hoist, as required, until tool will SLIDE engine on shift cable. Shift cable outer casing can FREELY all the way in and out of engine cou- be crushed causing difficult or improper shifting.

  • Page 83: Engine Connections

    When alignment is correct, tighten locknut or Engine Connections nut with lockwasher on each mount securely. IMPORTANT: When routing all wire harnesses and hoses, be sure they are routed and secured to avoid coming in contact with hot spots on en- gine and avoid contact with moving parts.
  • Page 84 2. Connect instrument harness to engine harness 3. Connect trim position sender leads from gimbal with hose clamp. Tighten clamp securely. housing to leads from engine harness. 72992 a - Brown/White (From Engine Harness) b - Black (From Engine Harness) 50113 c - Black (From Transom Assembly) d - Black (From Transom Assembly)
  • Page 85 5. Connect throttle cable using hardware retained c. Secure throttle cable with hardware (re- and adjust as follows: tained) as shown. Tighten cable end guide locknut until it bottoms out and then back off a. Place remote control handle(s) in neutral, idle one full turn.
  • Page 86 e. Return remote control throttle lever to idle po- 7. Connect MerCathode wires to MerCathode con- sition and check to ensure that throttle lever troller assembly as shown, if so equipped. Apply contacts idle speed adjustment screw. a thin coat of Quicksilver Liquid Neoprene to all connections.
  • Page 87 IMPORTANT: Be careful not to cross-thread or over tighten fittings. Earlier Style Control Valve: Torque large fitting to 20-25 lb. ft. (27-34 N·m) and small fitting to 96-108 lb. in. (11-12 N·m). 72026 a - Large Fitting b - Small Fitting Later Style Control Valve: Torque fittings to 23 lb.
  • Page 88 ENGINE 26790 181 CID (3.0L) 4 CYLINDER GM ENGINE Index...
  • Page 89 Table of Contents Page Page Cleaning ......3A - 17 Torque Specifications ....3A - 1 Inspection .
  • Page 90 Page Page Removal ......3A - 32 Camshaft ......3A - 38 Disassembly .
  • Page 91 Torque Specifications Fastener Location Lb. In. Lb. Ft. N·m Camshaft Sprocket Bolts Connecting Rod Cap Nuts Cylinder Head Bolts Note 1 Distributor Clamp Engine Coupler to Flywheel Flywheel Housing to Block Flywheel to Crankshaft Bolts Front Cover Bolts Front Mount to Block Main Bearing Cap Bolts Manifold to Head Note 2...

  • Page 92: Tools/Lubricants/Sealants

    Tools/Lubricants/Sealants MERCURY MARINE SPECIAL TOOLS 91-24697 Piston Ring Expander 91-63209 Torch Lamp KENT MOORE SPECIAL TOOLS J5892 Valve Spring Compressor (Head on) J8062 Valve Spring Compressor (Head off) J23738-A Valve Stem Seal Tester J8101 Valve Guide Cleaner J8814 Valve Guide Reamer (Standard) J5830-02 Valve Guide Reamer (.015 in.

  • Page 93: Engine Specifications

    Engine Specifications UNIT OF MEASUREMENT in. (mm) Model 3.0L/3.0LX Displacement 181 CID (3.0L) CYLINDER BORE Diameter 3.9995-4.0025(101.588-101.790) Production .0005(0.012) Max Out of Round Out of Round Service .002(0.05) Max Thrust Side .0005(0.012) Max Production Production Taper Relief Side .0005(0.012) Max Service .001(0.02) Max PISTON CLEARANCE...

  • Page 94: Crankshaft

    CRANKSHAFT Diameter 2.2979-2.294(58.367-58.404) Production .0002(0.005) Max Taper Taper M i J M i J Main Journal Service .001(0.02) Max Production .0002(0.005) Max Out of Round Out of Round Service .001(0.02) Max Production No.1-No.4 .001-.0024(0.025-0.060) Service No.5 .0016-.0035(0.041-0.088) M i B Main Bearing Clearance Production...

  • Page 95: Valve System

    VALVE SYSTEM Lifter Hydraulic Rocker Arm Ratio 1.75 to 1 Collapsed Tappet Gap 3/4 Turn Down from Zero Lash Intake Face Angle Face Angle Exhaust Seat Angle (Intake & Exhaust) Seat Runout (Intake & Exhaust) .002(0.05) Max Intake 1/16 (.0625in). (1.16 mm) Seat Width Seat Width Exhaust...

  • Page 96: General

    Displacement MCM 3.0L/3.0LX 181 (3L) Engine Identification The MerCruiser Model can be determined by looking at the LAST TWO LETTERS of the engine code stamped into the cylinder block. This code number is 72001 stamped on all MerCruiser power packages and re-...

  • Page 97: Priming Engine With Oil

    Priming Engine With Oil 1. Fill crankcase to proper level with the recom- mended engine oil. 2. Remove spark plugs. IMPORTANT: This applies to all power packages that have not been run within 6 months, replace- 3. Leave ignition key in ”OFF” position. ment of partial engines or after rebuilding an en- 4.

  • Page 98: Bearing Failures

    Bearing Failures Overlay Wiped Bright (Polished) Scratches Dirt Imbedded Sections into Bearing Scratched Lack of Oil Improper Seating Material by Dirt Radius Ride Craters or Pockets Overlay Gone from Entire Surface 70436 Tapered Journal Radius Ride Fatigue Failure Piston Failures PRE-IGNITION CAUSES 1.

  • Page 99: Detonation

    Engine failures, which result from the foregoing con- cases, results in pre-ignition. ditions, are beyond the control of MerCruiser; there- fore, no warranty will apply to failures which occur un- Use of low octane gasoline is one of the most com- der these conditions.

  • Page 100: Engine Mounts

    Engine Mounts Rocker Arm Cover Removal It may be necessary to remove exhaust manifold be- fore removing rocker arm cover. Refer to Section 7B for removal. 1. Disconnect crankcase ventilation hoses. 2. Remove any items that interfere with the removal of rocker arm covers.

  • Page 101: Rocker Arm/Push Rod

    Rocker Arm/Push IMPORTANT: Place rocker arm assemblies and push rods in a rack for reassembly in their origi- nal locations. Cleaning and Inspection 1. Clean parts with solvent and dry with compressed air. 2. Inspect all contact surfaces for wear. Replace all damaged parts.

  • Page 102: Valve Adjustment

    Valve Adjustment 5. Crank engine one revolution until pointer “0” mark and torsional damper mark are again in align- ment. This is No. 4 firing position. With engine in this position, the following valves may be ad- Engine Not Running justed: With valve cover removed, adjust valves when lifter No.

  • Page 103: Hydraulic Valve Lifters

    5. Repeat Steps 2-3-4 to adjust other valves. 3. General noise throughout valve train - this will, in most cases, be a definite indication of insufficient 6. Install valve covers, torque screws to 40 lb. in. oil supply or improper adjustment. (4.5 N·m).

  • Page 104: Cleaning And Inspection

    3. Make matching marks on all retainers and lifters Cleaning and Inspection as to location and orientation in bores, to allow 1. Thoroughly clean all parts in cleaning solvent and reassembly in exact position on camshaft lobes inspect them carefully. (so that the roller’s bearing and roller will roll in the same direction on the same lobe, if reused).

  • Page 105: Valve Stem Oil Seal/Valve Spring

    Valve Stem Oil Seal/Valve Replacement Oil Seal Head Installed Spring 1. Remove rocker arm cover. 2. Remove spark plug, rocker arm and push rod on cylinder to be serviced. 3. Place piston for that cylinder at TDC to prevent valves from dropping into the cylinder. 4.

  • Page 106: Cylinder Head

    NOTE: A light coat of oil on seal will help prevent CAUTION twisting when compressor tool is released. The head gasket may be holding cylinder head to block. Use care when prying off cylinder heads. IMPORTANT: Do not turn crankshaft while valve DO NOT damage gasket surfaces.

  • Page 107: Cylinder Head And Valve Conditioning

    7. Install as outlined: 3. Remove valves from cylinder head and place in a rack, in order, for reassembly in their original lo- a. Intake manifold. cations. b. Rocker arm covers. c. Exhaust manifolds. d. Spark plugs. e. Any components removed from front or rear of cylinder heads.

  • Page 108: Inspection

    5. Thoroughly clean valve guides with valve guide IMPORTANT: Cylinder head-to-block gasket sur- cleaner (J-8101). face should be resurfaced if warped more than specified. When head resurfacing is required, cylinder head-to-intake manifold gasket surface on head must be milled to provide proper align- ment between intake manifold and head.

  • Page 109: Rocker Arm Studs

    Rocker Arm Studs Valve Guide Bore Repair Rocker arm studs with damaged threads or with loose IMPORTANT: Be sure to measure valve stem di- fit in cylinder heads should be replaced with new, ameter of both the intake and exhaust valve, as oversize studs.

  • Page 110: Valve Seats

    Valve Seats Several different types of equipment are available for refacing valves. The recommendation of the man- Valve seat reconditioning is very important, since ufacturer of the equipment being used should be seating of valves must be perfect for engine to deliver carefully followed to attain proper results.
  • Page 111 6. While compressing valve spring with valve spring 9 - Intake Valve 10 -Exhaust Valve compressor, install oil seal in lower groove of valve stem, making sure seal is not twisted. A light 8. Check installed height of valve springs using a coating of oil will help prevent twisting.

  • Page 112: Dipstick Specifications

    Dipstick Specifications Oil Pan All Engines UNIT OF MEASUREMENT In. (mm) (13) 25-7/16 (646) a - 181 CID (3.0L) Engines - 1 piece oil pan gasket 26-7/8 Removal (682) FULL 1. Disconnect battery. (19) NOTE: Removal of engine from boat may be re- quired.

  • Page 113: Oil Pump

    NOTE: A one-piece oil pan gasket may be reused if 4. If pickup screen and pipe assembly requires re- it is still pliable and is not cracked, torn or otherwise placement, mount pump in a soft-jawed vise and damaged. extract pipe from pump. 4.

  • Page 114: Installation

    5. Install pump cover and torque attaching bolts to 4. Remove torsional damper with torsional damper 80 lb. in. (9 N·m). remover and installer. 6. Turn extension shaft by hand to check for smooth operation. Installation 1. Install pump, with extension shaft, to rear main bearing, aligning extension shaft with distributor drive shaft.

  • Page 115: Crankcase Front Cover/Oil Seal

    c. Install torsional damper on crankshaft by turn- INSTALLATION ing nut until it bottoms out. IMPORTANT: Correct rotation oil seal must be used to prevent oil leak. 1. Apply Quicksilver Perfect Seal to seal retainer mating surface and apply grease to seal lips. 2.

  • Page 116: Removal

    Crankcase Front Cover 2. Coat both sides of front cover gasket with Quick- silver Perfect Seal and place in position on en- gine. Removal 3. Install front cover, making sure holes in cover align with dowel pins in block. Torque front cover 1.

  • Page 117: Inspection

    3. Remove MCM coupler. c. Maximum runout - .008 in. (0.203 mm). 4. Remove flywheel. 72349 Alpha One Coupler 72353 a - .008 in. (0.203 mm) Max. Runout Inspection b - Push Flywheel and Crankshaft Forward as Far as It Will Go when Taking Reading 1.

  • Page 118: Rear Main Oil Seal

    Rear Main Oil Seal Installation 1. Apply Quicksilver Perfect Seal to seal retainer The rear crankshaft oil seal can be replaced without mating surface. Apply grease to seal lips. removing the oil pan or rear main bearing cap from engine. 2.

  • Page 119: Main Bearings

    Main Bearings Checking Clearances To obtain accurate measurements while using Plasti- IMPORTANT: Before removing main bearing caps gage, or its equivalent, engine must be out of the boat or connecting rod caps, mark them for reassemb- and upside down so crankshaft will rest on the upper ly in their original locations.

  • Page 120: Main Bearing Replacement

    5. On the edge of the gauging plastic envelope there 9. Proceed to the next bearing. After all bearings is a graduated scale which is correlated in thou- have been checked, rotate the crankshaft to see sandths of an inch. Without removing the gauging that there is no excessive drag.

  • Page 121: Inspection And Replacement

    Inspection and Replacement c. Place a piece of gauging plastic, the length of the bearing (parallel to the crankshaft), on the crankpin or bearing surface as shown. Posi- IMPORTANT: Before you remove the connecting tion the gauging plastic in the middle of the rod cap, mark the side of the rod and cap with the bearing shell.

  • Page 122: Connecting Rod/Piston Assembly

    6. If the clearance exceeds specifications, select a Connecting Rod/Piston new, correct size bearing and measure the clear- Assembly ance. Be sure to check what size bearing is being re- moved in order to determine proper replacement Removal size bearing. If clearance cannot be brought to within specifications, the crankpin will have to be 1.
  • Page 123 Disassembly PISTONS NOTE: Cylinder bore and taper must be within speci- 1. Disassemble piston from connecting rod using fications before pistons can be considered for re-use. piston pin remover as shown. 1. Clean varnish from piston skirts with a cleaning solvent.
  • Page 124 6. Proper clearance of piston ring in its piston ring Reassembly groove is very important to provide proper ring ac- tion and reduce wear. Therefore, when fitting new PISTONS AND PISTON PINS rings, clearances between ring and groove sur- faces should be measured. See “Specifications.” IMPORTANT: When reassembling pistons and connecting rods, the following must be kept in mind.
  • Page 125 1. Assemble piston to connecting rod using piston 1. Slip compression ring in cylinder bore, then press pin remover as shown. Follow instructions ring down into cylinder bore about 1/4 in. (6 mm) supplied with kit. (below ring travel). Be sure that ring is square with cylinder wall.
  • Page 126 Install top compression ring with marked side 4. Install each connecting rod and piston assembly up, using ring expander. in its respective bore. Install with connecting rod bearing tangs toward outside of cylinder block. Use piston ring compressor to compress rings. Installation Guide connecting rod into place on crankshaft journal with connecting rod bolt guide.
  • Page 127 8. Install as previously outlined: 10. Remove crankshaft gear as shown. a. Oil pump. b. Dipstick and oil pan. c. Cylinder heads. d. Intake manifold. e. Distributor. 9. Fill crankcase with oil. Refer to SECTION 1 - “Maintenance.” 10. Torque rocker arm nuts to 20 lb. ft. (27 N·m). 74476 Crankshaft 11.
  • Page 128 2. Install main bearings in engine block as shown. Flywheel housing. k. Starter. 10. Install new oil filter. Fill crankcase with oil. Crankshaft Sprocket Removal 72359 1. Remove torsional damper and crankcase front a - Lower Bearing Insert cover as previously outlined. b - Upper Bearing Insert c - Oil Groove 2.
  • Page 129 4. Remove valve mechanism as previously out- IMPORTANT: Support camshaft carefully when lined. removing to protect camshaft bearings. 5. Position indicator with ball socket adaptor tool on push rod. Be sure that push rod is in lifter socket. 74438 72907 a - Ball Socket Adaptor Tool (J-8520-1) a - Timing Marks 6.
  • Page 130 3. Inspect camshaft gear and thrust plate for wear or CAUTION damage. Measure camshaft end play .001 - .005 Position thrust plate so that woodruff key in shaft in. (0.03-0.1 mm) does not damage plate when shaft is pressed out of gear.
  • Page 131 Installation 5. Check backlash between timing gear teeth with a dial indicator. Backlash should not be less than 1. Install camshaft and gear assembly in engine .004 in. (0.010 mm) or more than .006 in. (0.15 block, being careful not to damage camshaft bearings or camshaft.
  • Page 132 Camshaft Bearings Inspection Clean camshaft bearing bores in cylinder block with solvent and blow out with compressed air. Be sure Removal grooves and drilled oil passages are clean. Camshaft bearings can be replaced while engine is disassembled for overhaul or without complete disas- Installation sembly.
  • Page 133 b. Index center camshaft bearing, then position 2. Installing front and rear bearings: appropriate size remover and installer tool in a. Install appropriate size remover and installer bearing and thread puller screw into tool. Be tool on drive handle. sure at least 1/2 in. (13 mm) of threads are en- b.

  • Page 134: Cylinder Block

    Cylinder Block Cleaning and Inspection 1. Remove all engine components as previously outlined. 2. Wash cylinder block thoroughly in cleaning sol- vent and clean all gasket surfaces. 3. Remove oil gallery plugs and clean all oil pas- sages. 4. Remove expansion plugs. NOTE: These plugs may be removed with a sharp 72385 punch, or they may be drilled and pried out.
  • Page 135 3. If cylinders have less than .005 in. (0.127 mm) ta- per or wear, they can be conditioned with a hone and fitted with high limit standard size piston. A cylinder bore of more than .005 in. wear or taper may not clean up entirely when fitted to a high limit piston.
  • Page 136 4. Permanently mark piston (for cylinder to which it b. Measure piston diameter at skirt across cen- has been fitted) and proceed to hone cylinders ter line of piston pin as shown. and fit remaining pistons. IMPORTANT: Handle pistons with care and do not attempt to force them through cylinder until cylin- der is honed to correct size, as this type piston can be distorted by careless handling.

  • Page 137: Electrical Systems

    ELECTRICAL SYSTEMS 72079 STARTING SYSTEM Index...
  • Page 138 Table of Contents Page Page Armature Tests ..... . 4A - 14 Identification ......4A - 1 Field Coil Tests .

  • Page 139: Identification

    Identification 3. Inspect starter motor drive housing, replace if necessary. The starter identification number is located as shown. 72789 74517 a - Inspect This Area For Cracks a - Delco Number Delco-Remy Starter Motor 50-99417A–– STARTER BRACKET 72059 a - Starter Identification Number Delco PG 200 Starter Motor 50-812429A––...

  • Page 140: Replacement Parts Warning

    WARNING Electrical, ignition and fuel system components Hydrogen gases that escape from the battery dur- on your MerCruiser are designed and manufac- ing charging are explosive. Be sure that battery tured to comply with U.S. Coast Guard Rules and area is well ventilated and that bilge blower is in Regulations to minimize risks of fire and explo- operation when charging.

  • Page 141: Testing

    Testing Hydrometer Test Load Test WARNING Test battery in well ventilated area as gases given A strong battery must be maintained. If battery shows off by battery are hazardous. less than 9-1/2 volts when under starting load,(at 80 F 27 C)it should be recharged. Check with DC volt- 1.

  • Page 142: Storage

    HYDROMETER READINGS Storage BATTERIES TESTED BELOW IS DEAD NEEDS FULL 1. Remove battery and clean exterior. CHARGING CHARGED 2. Check fluid level and fill if low. 3. Cover terminals and bolts with light coat of grease. 4. Set battery on wood or in carton; store in cool, dry place.

  • Page 143: Charging Guide

    Charging Guide 12 Volt Battery Recommended Rate* and Time for Fully Discharged Condition Twenty Hour 5 Amperes 10 Amperes 20 Amperes 30 Amperes 40 Amperes 50 Amperes Rating 50 Ampere- Hours 10 Hours 5 Hours 2-1/2 Hours 2 Hours or less Above 50 to 15 Hours 7-1/2 Hours...

  • Page 144: Slave Solenoid Identification

    Switch Type Slave Solenoid Types There are two types of slave solenoids (“standard” or “switch”) used on MerCruiser engines. These en- gines use a standard type solenoid; do not substi- tute a switch type solenoid. The other engines use a slave solenoid to energize the starter motor sole- noid.

  • Page 145: Testing/Replacement

    Testing/Replacement 1. Using continuity meter, connect test leads as shown, and connect 12-volt battery with jumper leads as shown. 72630 2. If no meter movement is present, replace sole- noid. Index 90-816462 2-695 STARTING SYSTEM - 4A - 7...

  • Page 146: Specifications

    Specifications No Load Test Part Number Brush Spring Brush Spring (D l (Delco-Remy Min. Max. Min. Max. Tension Oz. (Grams) Volts Number) Amps Amps 50-812428A (9000762) 83-104 oz. 10.6 3,000 3,300 50-812604A (2353-2948 g) (9000768) 56-105 (1998317) 10.6 5400 10,800 (1588-2976) Pinion Clearance .010-.140 (0.25-3.5mm)

  • Page 147: Starter Motor (Exploded View)

    Starter Motor (Exploded View) 72806 18-Thru Bolt 1 - Drive End Housing 19-Insulated Holder - Field Frame Brush 2 - Drive End Housing Bushing 20-Field Frame Brush Ground Holder 3 - Thrust Collar 21-Field Frame Brush 4 - Retaining Ring - Pinion Stop Collar 22-Brush Lead Screw 5 - Pinion Stop Collar 23-Ground and Insulated Holders Support Package...

  • Page 148: Starting System Components

    Starting System Components 72929 a - Ignition Switch b - Neutral Safety Switch c - Starter Slave Solenoid d - Circuit Breaker e - Engine Ground Stud f - Starter Solenoid g - Wire Junction h - 20 Amp Fuse Index 4A - 10 - STARTING SYSTEM 90-816462 2-695...

  • Page 149: Positive Current Flow

    Positive Current Flow Periodic Inspection This is a general description of the positive current Cranking motor and solenoid are completely en- flow, from the battery and through the system until the closed in the drive housing to prevent entrance of starter motor cranks.

  • Page 150: Solenoid Switch

    Solenoid Switch IMPORTANT: DO NOT cut starter motor connec- tor strap terminal wire (to remove terminal) or wire will be too short. REMOVAL 1. Remove starter motor as outlined. 2. Remove screw from field coil connector and sole- noid attaching screws. 3.

  • Page 151: Starter Motor Disassembly

    Starter Motor Disassembly 3. Remove screws, center bearing plate and arma- ture. 1. Remove screw from field coil connector. 72634 a - Screws 72631 b - Bearing Plate a - Connector Screw c - Armature 2. Remove end frame thru bolts, end frame, washer 4.

  • Page 152: Cleaning And Inspection

    Cleaning and Inspection Armature Tests With starting motor completely disassembled, except TEST FOR SHORTS for removal of field coils, component parts should be cleaned and inspected. Field coils should be re- Check armature for shorts by placing on growler and moved only where defects are indicated by tests.

  • Page 153: Field Coil Tests

    2. If meter hand moves, armature is grounded and TEST FOR GROUND must be replaced. IMPORTANT: Be sure that positive brushes and leads do not contact field frame assembly during test, or false reading will result. 1. With continuity meter, place one lead on field con- nector bar and other lead on grounded brush.

  • Page 154: Reassembly

    Reassembly e. Assemble thrust collar on shaft with shoulder next to snap ring. Place thrust collar and retainer next to snap After all parts are thoroughly tested and inspected ring and using two pliers squeeze both until and worn or damaged parts replaced, reassemble snap ring is forced into retainer.

  • Page 155: Clearances

    Clearances 4. Push pinion back toward commutator end to elim- inate slack. 5. Measure distance between pinion and pinion re- PINION CLEARANCE tainer. Pinion clearance must be checked as follows after 6. If clearance is not within limits of .010-.140 in. reassembly of motor to insure proper adjustment.

  • Page 156: Installation

    Installation Delco PG200 and PG260 Starters 1. Place starter motor and solenoid assembly in po- sition and install mounting bolts. Torque bolts to Description 50 lb. ft. (68 N·m). 2. Fasten wires as outlined in wiring diagram. The Delco PG 200 and PG260 starter motor features 3.

  • Page 157: Pg200 Specifications

    PG200 Specifications No Load Test Brush Spring Delco I.D. Delco I.D. Engine Engine Tension Min. Number Rotation Volts Max. Amp Min. RPM Max. RPM Oz. (Grams) Amps 9000763 83-104 oz. 10.6 3000 3300 9000768 (2352-2948) Pinion Clearance .101-.160 (.025-4.06mm) Bearing Depth (Gear) .011-.014 (0.28-.038mm) Maximum Bearing Depth (Housing) .009-.017 (0.4mm) Maximum...

  • Page 158: Starting System Components

    Starting System Components 72929 a - Ignition Switch b - Neutral Safety Switch c - Starter Slave Solenoid d - Circuit Breaker e - Engine Ground Stud f - Starter Solenoid g - Wire Junction h - 20 Amp Fuse Index 4A - 20 - STARTING SYSTEM 90-816462 2-695...

  • Page 159: Pg200 Exploded View

    PG200 Exploded View 72079 1 - Field Frame (with Permanent Magnets) 11- Drive 2 - End Frame 12 - Collar 3 - Ball Bearing 13 - Retaining Ring 4 - Brushes with Holder 14 - Thrust Collar 5 - Brush Spring 15 - Drive Housing* 6 - Armature 16 - Roller Bearing...
  • Page 160 PG260 Exploded View 1 - Screw (2) 2 - End Cap 3 - Brushes with Holder 4 - Armature 5 - Field Frame (with Permanent Magnets) 6 - Washer 7 - Shield 8 - Planetary Gears 9 - Shaft 10 - Gear 11- Drive 12 - Collar 13 - Retaining Ring...

  • Page 161: Solenoid Switch

    3. Remove starter mounting bolts. CAUTION 4. Pull starter assembly away from flywheel and re- The starter motor is designed to operate under move from engine. great overload and produce a high horsepower for its size. It can do this only for a short time, since considerable heat accumulates and can PG200 Disassembly cause serious damage.
  • Page 162 NOTE: Permanent magnets inside field frame will be 6. Use a screwdriver, as shown, to disengage shift holding armature in place. lever from drive. 72062 72064 a - Armature b - Field Frame a - Shift Lever 4. Pull end frame off bearing. 7.

  • Page 163: Cleaning And Inspection

    8. Remove gear from shaft assembly. 4. Inspect all roller bearing surfaces for wear. Check that bearings roll freely. If any roughness is felt, replace bearings. 5. Inspect planetary gear assembly. Gears must mesh easily and roll freely with no binding. Armature Tests TEST FOR SHORTS Check armature for shorts by placing on growler and...

  • Page 164: Armature Bearing (Commutator End)

    2. If meter hand moves, armature is grounded and INSTALLATION must be replaced. IMPORTANT: Brush holder must be installed on armature before installing armature bearing. Using the correct size driver, press on inner bearing race until it contacts shoulder of armature shaft. Gear Bearing REMOVAL Using the correct size driver, press bearing out of...

  • Page 165: Shaft Assembly Bearing

    Shaft Assembly Bearing INSTALLATION 1. Using the correct size driver, press bearing into housing, from direction shown, to depth specified. IMPORTANT: Roller bearing is not replaceable. If bearing is defective, replace entire shaft assem- bly. Apply Quicksilver 2-4-C Marine Lubricant with Teflon to bearing before starter reassembly.

  • Page 166: Pg200 Reassembly

    REMOVAL PG200 Reassembly 1. Remove armature bearing as previously de- scribed. 1. Install end frame on brush holder. Align holes of end frame with holes of brush holder. Tighten 2. Remove brush holder. screws securely. INSTALLATION 1. Push each brush up into its guide to allow spring to hold it in place, as shown.
  • Page 167 3. Coat roller bearings and gear with a small amount d. Position snap ring on upper end of shaft and of Quicksilver 2-4-C Marine Lubricant with Teflon. hold in place with block of wood. Strike wood block with hammer, thus forcing snap ring over end of shaft.

  • Page 168: Standard Starter Slave Solenoid

    7. Insert shaft and drive assembly into drive hous- IMPORTANT: Do not overtighten thru bolts. Over- ing. Pins of drive must be snapped into holes of tightening will bend end frame. shift lever. Thrust collar must be in place before shaft is inserted in housing roller bearing.

  • Page 169: Installation

    4. Connect 12 volt battery positive (+) lead to sole- Installation noid switch terminal and negative (–) lead to sole- noid frame. IMPORTANT: Install special mounting shim (if 5. Momentarily touch a jumper lead from solenoid equipped) between starter motor and engine motor to starter motor frame.
  • Page 170 ELECTRICAL SYSTEMS 71855 IGNITION SYSTEM Index...
  • Page 171 Table of Contents Page Page (DDIS) Digital Distributorless Identification ......4B - 1 Ignition System .

  • Page 172: Identification

    DELCO EST (ELECTRIC SPARK TIMING) Replacement Parts Warning WARNING Electrical, ignition and fuel system components on your MerCruiser are designed and manufac- tured to comply with U.S. Coast Guard Rules and Regulations to minimize risks of fire and explo- sion.

  • Page 173: Spark Plugs

    3.0L Breaker Point Ignition Distributor Prestolite Distributor System Model 3.0L Condenser* .18 - .25 mfd Torque Specifications Point Dwell 39 - 45 Fastener Location Lb. Ft. Point Gap .016 in. (0.5mm) Distributor Clamp 3/8-16 Point Spring Tension 20 - 27 oz. (567 - 765 g) Spark Plugs (14 mm) Timing...

  • Page 174: Distributor Advance Curves

    Distributor Advance Curves IMPORTANT: Distributor advance curve charts do not include the initial engine timing. Basic initial timing must be added to chart for total advance MCM 3.0L with Prestolite curve. Distributor Distributor Advance: 16 Initial Timing: 8 BTDC IMPORTANT: The spark advance is controlled by Total Advance: 24 @ 4100 RPM the ignition module.

  • Page 175: Precautions

    Precautions IMPORTANT: Tapered seat spark plugs are not in- terchangeable with non-tapered (with gasket) WARNING spark plugs. When performing the following procedure, be 4. Clean spark plug seating area. DO NOT use gas- sure to observe the following: kets on taper seat plugs. Install spark plugs and Be sure that engine compartment is well ven- torque to 15 lb.

  • Page 176: Contact Points

    Contact Points 2. High voltage causes excessively high current flow thru contact points which burns them rapidly. 1. Examine contact points for dirt, wear, pitting and High voltage can result from improperly adjusted misalignment. Dirty points should be cleaned. or inoperative voltage regulator. Normal point condition is an overall grey color on 3.

  • Page 177: Replacement

    Replacement 8. Check point spring tension (20-27 oz.) 567-765g. 1. Remove primary and condenser lead wires from contact point terminal. 2. Remove contact set attaching screw and lift con- tact point set from breaker plate. 3. Clean oil smudge and dirt from breaker plate. IMPORTANT: Carefully wipe protective film from point set prior to installation.
  • Page 178 POINT ADJUSTMENT WITH IMPORTANT: Cam angle increases as point open- FEELER GAUGES ing is decreased and vice versa. 1. Rotate distributor until rubbing block rests on peak of cam lobe, which will provide maximum breaker point opening. 2. Insert correct feeler gauge between breaker points.

  • Page 179: Condenser

    Condenser Distributor Repair 1. Use Magneto Analyzer for test. Removal 2. Test condenser for the following: 1. Disconnect distributor primary lead from coil ter- a. Condenser capacity test (.18-.25 mfd). minal. b. Condenser leakage and short test. 2. Remove distributor cap and rotor. c.

  • Page 180: Disassembly

    Disassembly Advance Weights and Components Reassembly IMPORTANT: It is not necessary to disassemble distributor any further than required to complete 1. Replace centrifugal advance, as necessary. repairs. 2. Lubricate shaft with engine oil. Install main shaft in distributor housing. 1. Remove condenser and breaker points from breaker plate.

  • Page 181: Distributor Installation

    Distributor Installation 3. Position rotor to point toward front of engine (with distributor housing held in installed attitude), then turn rotor counterclockwise approximately Engine Not Disturbed 1/8-turn more to the left and push distributor down to engage camshaft. It may be necessary to ro- 1.
  • Page 182 IMPORTANT: GM engine timing marks (on tab) are in 2-degree increments. Timing must be set on the “before” side of “0” (Top Dead Center). 72328 a - Degree Marks b - Timing Mark 5. Adjust timing by loosening distributor clamp and rotating distributor body as required until timing mark on damper or pulley lines up with the mark on tab specified in “Specifications.”...

  • Page 183: (Ddis) Digital Distributorless Ignition System

    (DDIS) Digital Distributorless Tools/Lubricants/Sealants Ignition System Mercury Marine Special Tools Description Part Number Specifications Dwell Meter 91-59339 Magneto Analyzer 91-76032 COIL Remote Starter Switch 91-52024A1 Description Specification Timing Light 91-99379 Primary Resistance 1.9-2.5 Ohms *1 Volt/Ohm Meter 91-99750 Secondary Resistance 11.3 - 15.5 Ohms *2 Timing Jumper 91-818812A1...

  • Page 184: Description

    Description The ignition amplifier controls coil output, spark ad- vance, and limits engine speed to approximately The Digital Distributorless Ignitions System (DDIS) 5000 RPM. replaces the conventional point style ignition system. The ignition coil is actually two coils in one with four A motion sensor replaces the conventional distributor high voltage towers.

  • Page 185: Spark Advance Control

    Spark Advance Control Advance Curve Chart (Reference Only) IMPORTANT: The ignition amplifier controls spark advance above 1000 RPM. There is no ad- IMPORTANT: Advance curve charts do not in- justment. Initial timing must be set below 1000 clude the initial engine timing. Basic initial timing RPM.

  • Page 186: Spark Advance Control

    Spark Advance Control Advance Curve Chart (Reference Only) IMPORTANT: The ignition amplifier controls spark advance above 1000 RPM. There is no ad- IMPORTANT: Advance curve charts do not in- justment. Initial timing must be set below 1000 clude the initial engine timing. Basic initial timing RPM.

  • Page 187: Components Tests

    Components Tests 2. Disconnect engine harness form ignition amplifi- er. With ignition switch in the “RUN” position, check voltage at terminal from engine harness. IMPORTANT: Check spark plugs and spark plug Reading should be battery voltage. wires before the DDIS system. Use Multi-Meter 91-99750 to test DDIS components.

  • Page 188: Ignition Coil

    Ignition Coil b. Measure resistance between towers as shown. NOTE: Ignition switch must be in the “OFF” position when testing ignition coil. 1. Primary coil resistance: a. Disconnect coil from ignition amplifier. b. Measure resistance between coil connector terminals as shown. 74672 * At Room Temperature 68 F (20 C) 1 Ohmmeter set on the Rx1000 Scale...

  • Page 189: Motion Sensor

    b. Measure resistance between each high volt- IMPORTANT: Motion sensor must be at room tem- age tower and engine ground. Minimum re- perature, 68 F (20 C), when testing. sistance - 10 megohms. Motion Sensor NOTE: Motion sensor is factory set and not adjust- able.

  • Page 190: Motion Sensor

    Motion Sensor 2. Align hole [not roll pin hole] in gear with notch on motion sensor housing. Install new gasket. Apply Quicksilver 2-4-C Marine Lubricant with Teflon to Removal gear. 1. Disconnect wires (a). 74390 74537 a - Hole b - Notch in Motion Sensor Housing a - Wires NOTE: When installing motion sensor it may be nec- 2.

  • Page 191: Ddis Ignition Timing

    4. Reinstall cover. Tighten screws securely. 3. Adjust timing by loosening clamp and rotating motion sensor, as required, until timing mark on 5. Connect wires. pulley aligns with 8 BTDC mark on tab. Torque clamp bolt to 20 lb. ft. (27 N·m) , and recheck loca- tion of timing mark.

  • Page 192: Delco Est Ignition

    Delco EST Ignition Spark Plugs Spark Plug Gap .035 In. (0.9 mm) Torque Specifications AC-MR43T Fastener Location Lb. Ft. 3.0L NGK-BR6FS Champion RV15YC4 Distributor Clamp 3/8-16 AC-MR43LTS Spark Plugs (14 mm) 3.0LX NGK-BPR6EFS Champion RS12YC Tools/Lubricants/Sealants GM 4-Cylinder In-line Firing Mercury Marine Special Tools Description Part Number...
  • Page 193 Only three of the four terminals of the second connector are used by MerCruiser (one for the shift interrupt and two white leads are used to “freeze” advance for prop- erly setting initial timing). Inside the distributor, the pick-up coil attaches to the module at a molded prong connector.

  • Page 194: Component Tests

    Component Tests 5. Set ohmmeter to “Rx100” high scale. Connect ohmmeter to 12 volt terminal (b) and to coil high The following tests can be made with the distributor tension post (a). Reading should be between and coil mounted on or off the engine. The test proce- 7800 and 8800 ohms.

  • Page 195: Mcm 3.0L, 3.0Lx With Est

    MCM 3.0L, 3.0LX with EST Module Part Number: 811637 Module Advance: See Notice Initial Timing: 1 BTDC Total Advance: 23 NOTICE Advance curve includes initial timing. DO NOT add initial timing degrees to total advance degrees. MAX. MIN. 1000 1500 2000 2500 3000...
  • Page 196 Timing Procedure 3. Bypass the shift interrupt switch by disconnecting wires at shift interrupt switch. Temporarily join the engine harness wires together. IMPORTANT: Failure to follow the timing proce- dure instructions will result in improper timing causing performance problems and possible se- IMPORTANT: Do not fail to reconnect these two vere engine damage.
  • Page 197 ELECTRICAL SYSTEMS 72078 CHARGING SYSTEM Index...
  • Page 198 Table of Contents Page Page Identification ......4C - 1 Exploded View ......4C - 21 Replacement Parts Warning .

  • Page 199: Replacement Parts Warning

    Identification Replacement Parts Warning WARNING Electrical, ignition and fuel system components on your MerCruiser are designed and manufac- tured to comply with U.S. Coast Guard Rules and Regulations to minimize risks of fire and explo- sion. Use of replacement electrical, ignition or fuel sys-...
  • Page 200 Torque Specifications The rectifier bridge contains six diodes which are ar- ranged so that current flows from ground, through the stator and to the output terminal, but not in the oppo- Fastener Location Lb In. Lb. Ft. N·m site direction. End Frame Screws When current is supplied to the rotor field winding, Brush Setscrews...

  • Page 201: Precautions

    Precautions System Components The following precautions MUST BE observed when The alternator system consists of the alternator, bat- working on the alternator system. Failure to observe tery, the ignition switch and the wiring which connects these precautions may result in serious damage to these components.

  • Page 202: Periodic Maintenance

    Periodic Maintenance Drive Belt Tension Adjustment The following maintenance check should be per- formed every 50 hours or 60 days (whichever comes first) in fresh water areas or every 25 hours or 30 days in salt water areas. Alternator CAUTION 1.

  • Page 203: Troubleshooting Tests

    Troubleshooting Tests 2. Wiggle engine wiring harness while observing voltmeter. Meter should indicate approximate (Alternator on Engine) battery voltage and should not vary. If no reading is obtained, or if reading varies, check alternator Use the following tests in conjunction with the “Trou- output circuit for loose or dirty connections or bleshooting”...

  • Page 204: Sensing Circuit

    4. If reading is between .75 and 1.1 volts, rotor field 3. Voltmeter should indicate battery voltage. If bat- circuit probably is shorted or grounded. Disas- tery voltage is not present, check sensing circuit semble alternator and test rotor as outlined under RED/PURPLE lead for loose or dirty connection “Alternator Repair,”...

  • Page 205: Voltage Output Test

    5. Turn off accessories and reinstall coil wire. Start 2. Start engine and run at fast idle until engine engine and adjust engine speed to 1500-2000 reaches normal operating temperature. Adjust RPM. Quickly observe ammeter. Reading should engine speed to 1500-2000 RPM and observe be at least 30 amps.

  • Page 206: Alternator Repair

    4. Remove four nuts holding excitation and sensing Alternator Repair wires and Phillips screw. Remove regulator cover and install wires and nuts for testing. Connect a jumper wire from the ground stud to the brush ter- Removal minal on the lower right- hand side of the brush assembly.

  • Page 207: Exploded View

    Exploded View 72276 1 - Screw (3) 15 - Rectifier Assembly 2 - Nut (9) 16 - Flat Washer 3 - Flat Washer (4) 17 - Screw 4 - Sensing Wire (RED/PURPLE) 18 - Stator 5 - Excitation Wire (PURPLE) 19 - Rotor and Slip Rings 6 - Cover 20 - Retaining Plate...

  • Page 208: Disassembly

    Disassembly 3. Remove stud cover insulator, two nuts and tie strap from brush/regulator assembly. IMPORTANT: The following instructions are for 4. Remove two brush/regulator attaching screws complete disassembly and overhaul of the alter- and remove brush/regulator assembly. nator. In many cases, however, complete disas- sembly of alternator is not required and, in those cases, it is necessary only to perform the opera- tions required to repair or replace the faulty part.
  • Page 209 7. Separate rear end frame and stator assembly 9. Turn end frame over (stator upward) and remove from front end frame and rotor assembly using one Phillips head screw which secures rectifiers two thin blade screwdrivers (positioned 180 de- to end frame. grees apart from one another) at the locations shown.

  • Page 210: Cleaning And Inspection

    IMPORTANT: With alternator disassembled to 14. Remove front bearing from front end frame using this point, stator, rectifier, diodes, and rotor may an arbor press and a suitable size mandrel. (Dis- be tested, as explained under “Component Test- card bearing.) ing,”...

  • Page 211: Component Testing

    d. Rotor shaft and front end bearings - in- Component Testing spect for damaged seals, lack of lubrication, discoloration (from overheating) and exces- ROTOR sive side or end play. Bearing should turn 1. Test rotor field circuit for opens, shorts or high re- freely without binding or evidence of rough sistance (Test 1), using an ohmmeter (set on R x1 spots.

  • Page 212: Stator

    d. If reading is low, a short exists in the field cir- STATOR cuit. Inspect slip rings to be sure that they are IMPORTANT: Stator leads MUST BE discon- not bent and touching outer slip ring. Also, be nected from rectifier for this test. sure that excess solder is not shorting termi- 1.

  • Page 213: Rectifier And Diode Assembly

    RECTIFIER AND DIODE ASSEMBLY CAUTION NOTE: Failure of any component in tests following DO NOT use a test instrument with more than a 12 will require replacement of entire rectifier assembly. volt source (in the following test), as rectifier may be damaged.

  • Page 214: Condenser

    6. Connect one lead of an ohmmeter (set on R x1) Reassembly to the common side of the diode and the other 1. Install new front bearing into front end frame bear- lead to the other side, of one of the three diodes. ing bore using an arbor press.
  • Page 215 5. Assemble stator to rectifier by soldering the three 8. Position rear end frame and stator assembly over leads to the three rectifier terminals. front end frame and rotor assembly and align scribe marks on each (scribed during disassem- bly). Hand-press end frames together, then install four screws.
  • Page 216 10. Install brush/regulator assembly in rear end 12. Install cover with one Phillips head screw and two frame cavity and secure with two mounting nuts. Install two leads with nuts. screws, as shown. Tighten screws securely. Re- move drill bit to release brushes against slip rings. 72963 a - Phillips Head Screw b - Nuts (4)

  • Page 217: Installation

    2. Fasten alternator brace to alternator with bolt, Electrical, ignition and fuel system components washers and spacer (if used). DO NOT tighten on your MerCruiser are designed and manufac- bolt at this time. tured to comply with U.S. Coast Guard Rules and 3.

  • Page 218: Torque Specifications

    Torque Specifications scribed limits for properly charging the battery. Cur- rent output of the alternator does not require regula- tion, as maximum current output is self-limited by the Fastener Location Lb In. Lb. Ft. N·m design of the alternator. As long as the voltage is reg- Housing Screws ulated within the prescribed limits, the alternator can- Pulley Nut...

  • Page 219: Exploded View

    Exploded View PURPLE BLACK GREEN BROWN 73106 1 - Regulator and Leads 18 - Nut 2 - Screws (4) 19 - Washer 3 - Insulator Cap 20 - Insulating Washer 4 - Nuts (6) 21 - Insulator 5 - Washers (3) 22 - Negative Rectifier 6 - Condenser 23 - Positive Rectifier/Diode-Trio...

  • Page 220: System Components

    System Components Periodic Maintenance The alternator system consists of the alternator, bat- The following maintenance check should be per- tery, the ignition switch and the wiring which connects formed every 50 hours or 60 days (whichever comes these components. first) in fresh water areas or every 25 hours or 30 days in salt water areas.

  • Page 221: Drive Belt Tension Adjustment

    Drive Belt Tension Troubleshooting Tests Adjustment (Alternator on Engine) Use the following tests in conjunction with the “Trou- bleshooting” in Section 1. Before proceeding with the Alternator tests, however, perform the following checks to elimi- nate possible problem areas. Also observe “Precau- 1.

  • Page 222: Harness Voltage Test

    2. If voltage output does not fall within specifica- OPEN DIODE-TRIO TEST tions, alternator should be tested for probable 1. With ignition on and engine not running, check for cause and disassembled for repair. battery voltage at alternator output terminal (Test 1) and 1.5 to 3.0 volts at regulator terminal (Test 73081 a - Output Wire - ORANGE...

  • Page 223: Current Output Test

    CURRENT OUTPUT TEST 8. If reading is still low with jumper wire connected, perform “Voltage Output Test,” following, to deter- Perform this test to check if alternator is capable of mine if fault is in regulator or alternator. producing rated current output, using a 0-50 amp DC ammeter.

  • Page 224: Open Regulator Test

    OPEN REGULATOR TEST 4. Connect a jumper wire between field terminal (GREEN WIRE) and ground/ If 1.5 to 3.0 volts are IMPORTANT: This test requires removal of regu- present at regulator terminal, regulator is defec- lator. tive. If voltage is not present at regulator terminal, there is an open field circuit (brushes slip rings, CAUTION etc.).

  • Page 225: Alternator Repair

    Alternator Repair 2. Remove pulley, fan, woodruff key and spacer. WARNING Be sure that engine compartment is well-venti- lated and that there are no gasoline vapors pres- ent to prevent the possibility of an explosion and/ or a fire, should a spark occur. Removal CAUTION To prevent electrical system damage and/or...
  • Page 226 4. Remove brush holder. 8. Using a suitable holding fixture, separate front end frame and stator assembly from rear end frame using two thin blade screwdrivers (posi- tioned 180 degrees apart from each other) at the locations shown. 73091 a - Front End Frame 73090 b - Stator c - Rear End Frame...

  • Page 227: Cleaning And Inspection

    Cleaning and Inspection Front Bearing 1. Clean all parts with a clean, soft cloth. Do not use solvent, or electrical components may be dam- Removal aged. 1. Remove snap ring. 2. Inspect the following: 2. Use an arbor press to remove bearing from hous- a.

  • Page 228: Slip Rings/Rear Bearing

    Slip Rings/Rear Bearing Installation 1. Press new rear bearing all the way onto rotor shaft (until inner race contacts shoulder) with an arbor Removal press and a bearing driver that contacts inner bearing race only, as shown. Use extreme care to 1.

  • Page 229: Component Testing

    IMPORTANT: Press on the center of slip rings c. If continuity does exist, rotor field circuit is only. Do not bend terminals or pinch wires. grounded. Inspect slip ring terminals to be sure that they are not bent and touching rotor 3.

  • Page 230: Stator

    c. If reading is high or infinite (no meter move- Stator ment), high resistance or an open exists in the IMPORTANT: Stator leads MUST BE discon- field circuit. Check for poor connections be- nected from rectifiers and diode-trio for this test. tween field winding leads and slip ring termi- nals.

  • Page 231: Positive/Negative Rectifier And Diode-Trio Assembly

    3. A short in the stator is difficult to detect without 3. Check other two rectifiers in same manner. special equipment, because of the low windings 4. Replace assembly if any of the rectifiers is resistance. If all other electrical components test shorted or open.

  • Page 232: Condenser

    4. Replace assembly if any of the rectifiers is Condenser shorted or open. 1. Using Magneto Analyzer (91-76032) and accom- panying instructions, perform the following con- denser tests: a. Condenser Capacity Test (must be .5 mfd) b. Condenser Short or Leakage Test c.
  • Page 233 IMPORTANT: The insulators MUST BE installed 4. Install brush holder into rear end frame and slide as shown or damage to the alternator will result. forward to depress brushes against slip ring. In- sert two screws and tighten securely. 73085 a - Insulating Washers b - Insulators c - Negative Rectifier...

  • Page 234: Installation

    6. Place condenser on ground terminal and lead on 8. Using an oversized belt to protect the pulley, output terminal. Install insulator cap on regulator clamp alternator in vise as shown. Tighten pulley terminal. nut to 35-50 lb. ft. (48-68 N·m). 73108 73088 a - Oversized Belt...

  • Page 235: Battery Isolators

    BIA Low Voltage Wiring Stan- Battery isolators allow the addition of an auxiliary dard No. 125-79. (second) battery to the MerCruiser electrical system. The auxiliary battery is primarily used as a power NOTE: MerCruiser engines equipped with a 3-wire, source for various accessories installed on the boat.

  • Page 236: Battery Isolator Diagram

    Battery Isolator Diagram NOTE 1 Alternator with Voltmeter Circuit (Typical Wiring Shown) 72934 NOTE 1: Disconnect ORANGE Wire From Alternator ”BATT” Terminal. Splice Sufficient Guage Wire To The ORANGE Wire And Connect As Shown. Index 4C - 38 - CHARGING SYSTEM 90-816462 2-695...
  • Page 237 ELECTRICAL SYSTEMS 72747 INSTRUMENTATION Index...
  • Page 238 Table of Contents Page Page Oil Pressure ......4D - 5 Identification ......4D - 1 Testing .

  • Page 239: Identification

    Identification Special Information One of three distinct lines (Series) of Quicksilver Lighting Options gauges may be installed (if equipped with Quicksilver gauges). Aside from different gauge face appear- ances and styling, the back of the gauges and wiring COMMODORE AND INTERNATIONAL SERIES connections are different as shown.

  • Page 240: Qsi Series

    QSI SERIES Gauges These gauges are equipped with optional illumination lighting. Light bulb socket can be removed and con- Oil, Fuel and Temperature tacts can be aligned to be used with ignition switch lighting circuit +12 V or separate instrumentation IMPORTANT: If testing proves gauge to be defec- lighting circuit LT.

  • Page 241: Battery Gauge

    4. Turn ignition switch to OFF. 2. Connect negative (–) jumper lead from battery to gauge terminal G (GND). 5. Connect jumper wire from terminal G (GND) to terminal S (SEND). 3. Connect positive (+) jumper lead from battery to gauge terminal I or +12 V.

  • Page 242: Cruiselog Meter

    Cruiselog Meter IMPORTANT: Make sure that vacuum hose be- tween gauge and engine is not leaking and that all connections are tight. TESTING 1. Connect jumper wire from negative (–) battery Speedometer terminal to negative (–) gauge terminal. 2. Connect jumper wire from positive (+) battery ter- TESTING minal to positive (+) gauge terminal.

  • Page 243: Senders

    IMPORTANT: Do not distort case or bracket by Ohms Reading Oil Pressure over-tightening. (PSI) (PSI) Single Dual 8. Connect ground (BLACK) wire to ground termi- 227-257 113.5-128.5 nal, if gauge is not mounted in metal panel. 142-162.5 71-81.3 9. Connect other wires to gauge as shown in Sec- 91.7-113.6 45.9-56.8 tion 4E.

  • Page 244: Installation

    NOTE: While water cools you may recheck ohmme- WARNING ter readings. The following test involves the use of intense heat. Failure to follow appropriate procedures or warnings can cause burns which can result in se- vere personal injury. While performing the follow- ing test, observe these general precautions: Wear personal protective clothing such as rubber gloves, a non-flammable apron, and...

  • Page 245: Dual Station Sender Identification

    3. Connect TAN wire and coat with liquid neoprene. 4. With float arm in FULL position (arm horizontal), ohmmeter should read 30 ohms (+ 5 ohms). 72755 a - Ohmmeter Leads b - Vertical Float Arm a - TAN Wire 5.

  • Page 246: Capsule Type

    Capsule Type 6. Turn magnet clockwise until fuel capsule indicator reads FULL. Ohmmeter should read 30 ohms (+ 5 ohms). Fuel capsule is defective if not within TESTING specifica- 1. Disconnect wire from terminal on fuel tank cap- tions. sule. 2.

  • Page 247: Audio Warning System

    4. With key switch in START, continuity will exist be- c. If horn sounds, problem is in TAN/BLUE wire tween terminals B to A, B to I and B to C. back to engine or switches on engine. 5. If ignition key switch tests bad, unsolder wire con- nections and remove switch.

  • Page 248: Oil Pressure Switch

    Oil Pressure Switch 2. Switch should read no continuity. WARNING Refer to Section 4E for switch locations. Switch is nor- mally closed. The following test involves the use of intense heat. Failure to follow appropriate procedures or TESTING warnings can cause burns which can result in se- vere personal injury.
  • Page 249 b. Heat sand and observe temperature on ther- mometer. 72767 a - 48952 Switch with Red Mylar Sleeve b - 87-86080 Switch with Black Mylar Sleeve Switch Identification 4. Turn heat source off. Allow sand to cool. Note thermometer reading to ensure switch “opens” up at specified temperature.
  • Page 250 ELECTRICAL SYSTEMS 72938 WIRING DIAGRAMS Index...
  • Page 251 Table of Contents Page Page Wiring Colors for MerCruiser ....4E - 1 Breaker Point Ignition - Dual Station Wiring Diagrams ......

  • Page 252: Wiring Colors For Mercruiser

    Wiring Colors for MerCruiser BIA COLOR CODE AND ABBREVIATIONS WHERE USED BLACK (BLK) All Grounds BROWN (BRN) Reference Electrode-MerCathode ORANGE (ORN) Anode Electrode-MerCathode LIGHT BLUE/WHITE (LIT BLU / WHT) Trim- ”Up” Switch GRAY (GRY) Tachometer Signal GREEN/WHITE (GRN / WHT) Trim -”Down”...

  • Page 253: Wiring Diagrams

    Wiring Diagrams 3.0L Engine Wiring Diagram (Breaker Points Ignition) ALTERNATOR WATER TEMPERATURE SENDER OPTIONAL AUDIO WARNING WATER TEMPERATURE HEAT SWITCH CHOKE OIL PRESSURE SENDER SHIFT INTERRUPT OPTIONAL OIL SWITCH PRESSURE SWITCH STARTER SLAVE SOLENOID TERMINAL BLOCK CIRCUIT BREAKER ENGINE TRIM GROUND SENDER GROUND STUD ON...

  • Page 254: L/3.0Lx Engine Wiring Diagram (Ddis Ignition)

    3.0L/3.0LX Engine Wiring Diagram (DDIS Ignition) ALTERNATOR WATER TEMPERATURE SENDER OPTIONAL AUDIO WARNING WATER TEMPERATURE HEAT SWITCH CHOKE OIL PRESSURE SHIFT SENDER INTERRUPT OPTIONAL OIL SWITCH PRESSURE SWITCH STARTER SLAVE SOLENOID TERMINAL BLOCK CIRCUIT BREAKER ENGINE GROUND TRIM SENDER GROUND STUD ON GROUND SCREW ON ENGINE FLYWHEEL INNER TRANSOM...

  • Page 255: L/3.0Lx Engine Wiring Diagram (Est Ignition)

    3.0L/3.0LX Engine Wiring Diagram (EST Ignition) STYLE STYLE BOTTLE BOTTLE NOTE 1: Audio Warning System Standard On 3.0LX Models NOTE 2: Gray lead for use with service tachometer. A - Ignition Components B - Starting , Charging and Choke Components C - Audio Warning System Components D - Instrumentation Components Index...

  • Page 256: Instrumentation Wiring Diagram (Battery Meter Circuit)

    Instrumentation Wiring Diagram (Battery Meter Circuit) NOTE 1: Connect wires together with screw and hex nut. Tighten securely and coat with Liquid Neoprene to help control corrosion: when dry, slide neoprene sleeve over connection. NOTE 2: Power for a fused accessory panel may be taken from this connection. Load must not exceed 40 amps. Panel ground wire must be connected to instrument terminal that has an 8-gauge BLACK (ground) har ness wire connected to it.
  • Page 257 NOTE 1: Connect wires together with screw and hex nut. Tighten securely and coat with Liquid Neoprene to help control corrosion: when dry, slide neoprene sleeve over connection. NOTE 2: Power for a fused accessory panel may be taken from this connection. Load must not exceed 40 amps. Panel ground wire must be connected to instrument terminal that has an 8-gauge BLACK (ground) harness wire connected to it.
  • Page 258 NOTE 1: BROWN/WHITE wire is taped back at instrument end. If installing on boat that is equipped with MerCruiser Stern Drive, BROWN/WHITE wire is connected to the trim sender terminal block. Also can be used for an accessory (limit 5 amps).
  • Page 259 NOTE 1: BROWN/WHITE wire is taped back at instrument end. If installing on boat that is equipped with MerCruiser Stern Drive, BROWN/WHITE wire is connected to the trim sender terminal block. Also can be used for an accessory (limit 5 amps).
  • Page 260 NOTE 1: BROWN/WHITE wire is taped back at instrument end. If installing on boat that is equipped with MerCruiser Stern Drive, BROWN/WHITE wire is connected to the trim sender terminal block. Also can be used for an accessory (limit 5 amps).
  • Page 261 EST AND DDIS IGNITION - DUAL STATION USING A NEUTRAL SAFETY SWITCH IN BOTH REMOTE CONTROLS NOTE 2 TO WHT/GRN CONNECTION ON TERMINAL BLOCK AT NOTE 4 SHIFT PLATE CUT-OUT NOTE 3 SWITCH (ON ENGINE ROCKER ARM COVER) PRIMARY STATION WATER TACHOMETER BATTERY...

  • Page 262: Battery Meter Gauge

    Battery Meter Gauge Fuel Gauge and Sender WHITE PURPLE BLACK PINK 72814 PINK BLACK a - Lamp Mounting Hole b - PURPLE (or WHITE) Jumper Wire from This Terminal to “I” (or +) Terminal on Water Temperature or Oil Pressure Gauge c - BLACK Jumper Wire from This Terminal to Ground (–) Terminal on Water Temperature or Oil Pressure Gauge...

  • Page 263: Audio Warning System

    Audio Warning System Oil Pressure Gauge WARNING Buzzer is not external ignition-proof; therefore, DO NOT mount buzzer in engine or fuel tank com- part- ments. 72819 BIA Color Code Leads to – a BLACK (a) Ground (–) b PURPLE (b) Switched 12 Volt (+) Terminal c LIGHT BLUE (c) Sender Lead TAN/BLUE TAN/BLUE...
  • Page 264 FUEL SYSTEM FUEL PUMP Index...
  • Page 265 Table of Contents Page Page Fuel System Components (Typical) ..5A - 3 Identification ......5A - 1 Water Separating Fuel Filter .

  • Page 266: Identification

    Bearing Grease Loctite Pipe Sealant Electrical, ignition and fuel system components Obtain Locally with TEFLON on your MerCruiser are designed and manufac- tured to comply with U.S. Coast Guard Rules and Regulations to minimize risks of fire and explo- Specifications sion.

  • Page 267: Precautions

    Precautions Fuel Delivery System WARNING Recommendations Always disconnect battery cables from battery BEFORE working on fuel system to prevent fire WARNING or explosion. Boating industry standards (BIA, ABYC, etc.) fed- WARNING eral standards and Coast Guard regulations MUST BE adhered to when installing fuel delivery Be careful when changing fuel system compo- system.

  • Page 268: Fuel System Components (Typical)

    Fuel System Components Filter should be replaced when fuel flow is restricted or filter flow is questionable. DO NOT attempt to flush out filter. FUEL SYSTEM Replacement NOTICE Refer to “Precautions,” in this section, BE- FORE proceeding. 1. Disconnect battery cables from battery. 2.

  • Page 269: Fuel Pump Fuel Filter

    Fuel Pump Fuel Filter 9. Check for gasoline leaks. 10. If leaks exist, STOP ENGINE and recheck con- NOTICE nections. Refer to “Precautions,” in this section, BE- FORE proceeding. Testing Fuel Pump Replacement NOTICE Refer to “Precautions,” in this section, BE- INSPECTION FORE proceeding.

  • Page 270: Fuel Pump Replacement

    Fuel Pump Replacement Check for fuel leaks. 5. Install fuel outlet fitting (from old pump) into fuel pump. Removal 6. Install fuel line to fuel outlet fitting. Tighten secure- 1. Remove fuel inlet and outlet lines at fuel pump. 2. Remove sight tube. 7.
  • Page 271 FUEL SYSTEM 72681 MERCARB 2 BARREL CARBURETOR Index...

  • Page 272: For Information And Procedures On Troubleshoot

    Table of Contents Page Page Fuel Inlet Filter ..... . . 5B - 6 Identification ......5B - 1 Choke Inspection .

  • Page 273: Identification

    Identification Replacement Parts Warning WARNING Electrical, ignition and fuel system components on your MerCruiser are designed and manufac- tured to comply with U.S. Coast Guard Rules and Regulations to minimize risks of fire and explo- sion. Use of replacement electrical, ignition or fuel sys-...

  • Page 274: Specifications

    Specifications UNIT OF MEASUREMENT In. (mm) CARBURETOR ADJUSTMENT SPECIFICATIONS Engine Model 3.0L 3.0LX Carburetor Type MerCarb 36mm MerCarb 43mm MerCab 43mm MerCab 43mm 1389-9562 1389-815396 Carburetor Number 3310-805924 1389-815397 3310-806077 3310-806078 Float Level 3/8 (10) Spring Loaded 9/16 (14) (See Note) Needle Float Drop 1-3/32 (27) (See Note)

  • Page 275: High Altitude Re-Jetting

    High Altitude Re-Jetting Engine flooding problems, at idle RPM, are generally related to the altitude (above sea level) at which they are operated. If engine is running too rich at higher elevation, order a smaller jet from the chart. A jet stamped “165” is a 1.65 mm jet.

  • Page 276: Important Service Information

    Important Service Adjustable Accelerator Pump Lever Information This new 3-holed lever will allow you to change the amount of fuel delivered to the engine by the acceler- ator pump. The hole closest to the lever’s shaft will give the same amount of fuel as the single hole lever Flooding at Idle RPM did.

  • Page 277: Precautions

    Precautions Fuel Supply Connections WARNING CAUTION DO NOT operate engine without cooling water be- Always disconnect battery cables from battery ing supplied to water pickup holes in gear hous- BEFORE working on fuel system to prevent fire or ing, or water pump impeller will be damaged and explosion.

  • Page 278: Fuel Inlet Filter

    2. Clean and inspect: b. Fuel inlet filter nut and small gasket. a. Clean flame arrestor in solvent and blow dry c. Large gasket. with compressed air. d. Filter. b. Clean crankcase ventilation hoses. e. Spring. c. Inspect crankcase ventilation hoses for Small gasket - from inside filter nut.

  • Page 279: Choke Inspection

    Choke Inspection 2. With throttle valves completely closed, measure from flame arrestor mounting surface to top of The choke does not require any periodic mainte- pump rod. nance; however, if a choke malfunction is suspected, the following should be done: 1.

  • Page 280: Choke Setting

    Choke Setting 3. Using a .080 (5/64) in. drill rod, or or appropriate gauge,slide rod between upper edge of choke Normal choke setting is such that scribed mark on plate and air horn assembly. Rod should just slide cover is in line with long case mark on choke housing. through.

  • Page 281: Preliminary Idle Speed And Mixture

    Preliminary Idle Speed and Mixture Final Idle Speed and Mixture IMPORTANT: The following adjustments will pro- IMPORTANT: Boat must be in the water and en- vide a sufficient idle speed and mixture for start- gine at normal operating temperature to accu- ing engine.

  • Page 282: Repair

    4. With boat in open water, place remote control in IMPORTANT: Place a clean cloth in bores of car- forward gear, idle position. buretor to prevent dirt and foreign material from falling into bores. 5. Disconnect throttle cable barrel from anchor stud. Be sure not to lose spacer on anchor stud.
  • Page 283 7. Install throttle cable as explained in Section 2. 8. Install flame arrestor and crankcase ventilation hose. 9. Reconnect battery cables to battery. 10. Ensure that water is supplied to cooling system. Start engine and check for gasoline leaks. If leaks exist, STOP ENGINE IMMEDIATELY and re- check connections.
  • Page 284 72686 Index 5B - 12 - MERCARB 2 BBL CARBURETOR 90-816462 2-695...

  • Page 285: Exploded View Parts List

    Exploded View Parts List CHOKE HOUSING ASSEMBLY 1. Remove choke cover. 1- Rod - Accelerator Pump 2- Accelerator Pump Shaft and Lever Assembly 3- Washer (Outer) 4 Washer (Inner) 5- Screw 6- Washer 7- Screw 8- Spring 9- Filter 10-Gasket 11 -Gasket 12-Nut-Fuel Inlet 13-Choke-Rod...
  • Page 286 2. Remove accelerator pump rod retaining clip. Piv- ot rod (as required) until retaining ear on rod and slot in pump shaft and lever assembly align, al- lowing rod to be pulled out. 72286 a - Choke Rod b - Choke Lever c - Slot 4.
  • Page 287 5. Carefully lift air horn from float bowl assembly. 8. Check float weight as shown. 72400 72122 a - Air Horn Assembly b - Float Bowl Assembly 6. Invert air horn and carefully lay on bench. a - Grams Scale b - Float 7.
  • Page 288 10. Remove needle assembly. 12. Loosen accelerator pump screw. Slide pump shaft and lever assembly (and washer) out of air horn, then remove accelerator pump assembly. 72398 72287 a - Setscrew a - Needle Assembly b - Lever Assembly b - Needle Seat c - Pump Assembly 11.
  • Page 289 FLOAT BOWL ASSEMBLY 3. Remove main metering jets. 1. Remove accelerator pump return spring from pump well. 72291 a - Main Metering Jets b - Gaskets (Not Shown) IMPORTANT: Use care when removing venturi cluster to prevent damaging brass tubes which 72402 protrude from bottom of cluster.
  • Page 290 5. Using a needle-nose pliers, remove accelerator 2. Remove idle mixture adjusting needle and spring. pump check ball spring retainer. Turn float bowl over to remove spring and check ball. 72407 72293 a - Spring Retainer a - Idle Mixture Adjusting Needle b - Spring and Check Ball (Not Shown) b - Spring 3.
  • Page 291 Cleaning and Inspection 4. Carefully inspect all carburetor parts for wear and damage; pay particular attention to the following: IMPORTANT: DO NOT use a wire or drill to clean a. Float Needle and Seat: If float needle or seat jet passages or tubes in carburetor, as this may is worn or damaged, replace with new needle enlarge orifices and seriously affect carburetor and seat assembly.
  • Page 292 Reassembly 3. Turn float bowl assembly upside down and place new throttle body gasket on bowl, making sure gasket is properly positioned on location dowels. THROTTLE BODY ASSEMBLY IMPORTANT: DO NOT force idle mixture needle against seat as damage to needle and/or seat will result.
  • Page 293 FLOAT BOWL ASSEMBLY 3. Install venturi cluster in carburetor as shown. IMPORTANT: Place float bowl and throttle assem- blies in holding fixture to prevent throttle valves from being damaged. 1. Install check ball, spring, and retainer in passage as shown. Push retainer firmly into slots. 72397 a - Venturi Cluster b - Gasket...
  • Page 294 5. Install main metering jets with gaskets as shown. 7. Place accelerator pump spring in pump well. Tighten securely. 72291 a - Main Metering Jets 72402 b - Gaskets (Not Shown) a - Accelerator Pump Spring 6. Install power valve with new gasket. Tighten se- curely.
  • Page 295 2. Insert pump shaft and lever assembly (and wash- IMPORTANT: Float needle and needle seat are er) into air horn; then, align indexed hole in pump factory matched and tested and should be re- lever with shaft and lever assembly and slide placed as a set only.
  • Page 296 6. Install float assembly and hinge pin. Pivot float as- 3. Bend float arm up or down at point shown to ob- sembly up and down on hinge pin to ensure it tain specified dimension. moves freely. 72688 72297 a - Bend Float Arm at This Point a - Float Assembly 4.
  • Page 297 3. Bend float assembly tang, as shown, to obtain 6. Install seven short and one long air horn attaching specified dimension. screws. Tighten screws evenly and securely. 72690 a - Float Assembly Tang 4. Recheck BOTH float level and float drop. 5.
  • Page 298 8. Place idle cam on choke rod. 10. Place accelerator pump rod (end with ear) in hole in pump shaft and lever assembly. 72392 72393 a - Idle Cam b - Choke Rod a - Accelerator Pump Rod b - Pump Shaft and Lever Assembly 9.
  • Page 299 CHOKE HOUSING ASSEMBLY 2. Install choke cover. Make sure hook on end of choke coil engages with choke lever. Rotate 1. Install choke housing on air horn; tighten screws choke cover until index marks align as shown. securely. Install choke lever; tighten screw se- Tighten screws securely.
  • Page 300 COOLING SYSTEM 50628 SEAWATER COOLED MODELS Index...
  • Page 301 Table of Contents Page Torque Specifications ....6A - 1 Tools/Lubricants/Sealants ....6A - 1 Specifications .
  • Page 302 Torque Specifications Specifications Description lb. ft. Cooling System Capacity 9 (8.5) Power Steering Pump Thermostat (Brass) 143 F(62 C) Bracket Thermostat Cover Flush Cooling System Thermostat Housing Water Circulating Pump If engine is operated in salty, polluted or mineral laden Water Temperature waters, cooling system should be flushed periodically Sender...

  • Page 303: Stern Drive Seawater Pickup Pump

    Stern Drive Seawater Pickup Pump Thermostat Removal 1. Drain water from cylinder block and exhaust man- ifold. 2. Disconnect Hose from thermostat cover. 3. Remove thermostat cover attaching bolts and lock-washers, then remove and screws. 4. Remove thermostat from thermostat housing or cover.

  • Page 304: Installation

    4. Check opening and closing temperature of the e. Continue heat water until a temperature 25 F thermostat (using a tester similar to one shown (14 C) above temperature specified on ther- below), as follows mostat valve must be completely open at this temperature.

  • Page 305: Cold Weather Or Extended Storage

    Cold Weather Or Extended 2. Remove hose from power steering cooler. Storage CAUTION Cooling system must be completely drained for storage, or trapped water may cause freeze and/ or corrosion damage to engine. CAUTION If boat is in the water, seacock (water inlet valve), if so equipped, must be left closed until engine is to be restarted to prevent water from flowing back into cooling system and/or boat.

  • Page 306: Auxiliary Hot Water Heater Installation

    Auxiliary Hot Water Heater Installation When connecting a cabin heater or hot water heater to a MerCruiser engine, certain requirements must be met. Supply hose (from engine to heater) and re- turn hose (from heater to engine) MUST NOT EXCEED 5/8 in.
  • Page 307 2. Remove plug for thermostat housing at location 4. Install return fitting in hose and tighten hose shown. clamps securely. 73572 50628 a - Return Fitting 5. Connect hot water return hose to return fitting and a - Thermostat Housing b - Plug tighten hose clamps securely.

  • Page 308: Cooling System Flow Diagram

    Cooling System Flow Diagram MerCruiser engines with standard cooling systems then circulates the seawater through the block, head use seawater (water in which the boat is being oper- and manifolds, removing heat given off by these parts ated), to remove the heat given off by the engine.
  • Page 309 COOLING SYSTEM 73665 CLOSED COOLING MODELS Index...

  • Page 310: Notice

    Table of Contents Page Torque Specifications ....6B - 1 NOTICE Lubricants/Sealants ..... 6B - 1 Specifications .
  • Page 311 Torque Specifications The coolant recovery system keeps the reservoir full. Normal coolant overflow into recovery bottle is ap- proximately 1/2 pint (230 ml) during warm-up. The coolant recovery system draws coolant back into the Description lb. in. lb. ft. reservoir from the recovery bottle as the engine cools. Drain Plugs Securely As long as there is coolant in the recovery bottle, the...

  • Page 312: Pressure Cap Maintenance

    IMPORTANT: ALCOHOL OR METHANOL BASE ANTIFREEZE OR PLAIN WATER ARE NOT REC- OMMENDED FOR USE IN COOLING SYSTEM AT ANY TIME. In areas where ethylene glycol is not available, and the possibility of freezing does not exist, it is permissible to use a solution of rust in- hibitor and pure, soft water (mixed to manufactur- er’s recommendations).

  • Page 313: Testing Closed Cooling System

    Testing Closed Cooling 3. Clean inside of filler neck to remove any deposits or debris. Examine lower inside sealing surface System for nicks or other damage. Surface must be per- fectly smooth to achieve a good seal between it and rubber seal on cap. Also check locking cams Testing Coolant for Alkalinity on sides of filler neck to be sure that they are not bent or damaged.

  • Page 314: Testing For Cylinder Head Gasket Leak

    a. Start engine. Re-pressurize system to pre- a. During Idle and Warm-Up: Some coolant viously specified amount and observe pres- and/or air will leave the reservoir. sure gauge on tester. If needle in gauge vi- b. During Cruising Speed (2500-3500 RPM): brates, compression or combustion is leaking Coolant and/or air leaving the reservoir into closed cooling section from a leak in the...

  • Page 315: Testing Pressure Cap

    2. Remove closed cooling circuit hoses and inspect 4. Check that locking tabs on cap are not bent or the tubes just inside the nipples. Because the damaged. complete exchanger cannot be inspected, the 5. Using a cooling system pressure tester (similar to heat exchanger should be replaced if blockage is one shown), test cap to be sure that it releases at suspected.

  • Page 316: Thermostat

    Thermostat Testing 1. Clean thermostat in soap and water to remove Removal any deposits or debris. 2. Inspect thermostat for corrosion or other visible 1. Drain coolant from cylinder block and exhaust damage. manifold. 3. If thermostat is suspected of producing insuffi- 2.

  • Page 317: Installation

    4. Check opening and closing temperature of ther- Installation mostat (using a tester similar to the one shown), 1. Remove thermostat housing and gaskets. Dis- as follows: card gaskets. a. Fill tester to within 1 in. (25 mm) of top with tap 2.

  • Page 318: Closed Cooling Section

    Closed Cooling Section IMPORTANT: A wire should be inserted into drain holes to ensure that foreign material is not ob- Closed cooling section of closed cooling system structing the drain holes. On later models with should be kept filled year-round with recommended two piece petcock, removal of petcock may be re- coolant solution.

  • Page 319: Draining Diagram

    Draining Diagram 73665 a - Remove and Lower Hoses To Drain b - Remove Drain Plugs Repeatedly Clean Out Holes Using A Stiff Piece Of Wire, Until Entire System Is Drained. Index 90-816462 2-695 CLOSED COOLED MODELS - 6B - 9...

  • Page 320: Cleaning System

    Cleaning System 2. Remove bolts which secure end plate to each end of heat exchanger, then remove end plates, seal washers and gaskets. Discard seal washers and Closed Cooling Section gaskets. Clean gasket material from end plate and heat exchanger. Closed cooling section of the cooling system should be cleaned at least once every two years or whenever decreased cooling efficiency is experienced.

  • Page 321: Flushing Seawater Section Of Closed Cooling System

    1. Connect flushing attachment as follows: CAUTION NOTE: If flushing cooling system with boat in water, Avoid seawater pickup pump impeller damage. raise drive unit to trailer position, install flushing at- DO NOT operate engine without water being tachment and lower drive unit to full IN/DOWN posi- supplied to seawater pickup pump.

  • Page 322: Draining Seawater Section Of Closed Cooling System

    4. Shut off tap water. Remove hose and flushing at- 1. Close seacock (if so equipped) or disconnect and tachment from drive unit. On belt driven seawater plug seawater inlet hose. pickup pump models, also remove hose and 2. Check that engine is as level as possible to en- flushing attachment from pump inlet.

  • Page 323: Recommissioning

    5. If equipped with 3 in. (76 mm) or 6 in. (152 mm) 9. Insert a small wire (repeatedly) to make sure that risers, remove drain plug as shown from riser. vent holes and water drain holes and passages (as shown) are unobstructed and open. 73175 a - Drain Plug (Removed) 6.

  • Page 324: Filling Closed Cooling Section

    3. Perform all lubrication and maintenance specified CAUTION for completion “At Least Once Yearly” in mainte- Avoid seawater pickup pump impeller damage nance chart, except items which were performed and subsequent overheating damage to stern at time of engine layup. drive unit.

  • Page 325: Exhaust System

    EXHAUST SYSTEM MANIFOLD Index...
  • Page 326 Table of Contents Page Torque Specifications ....6C -1 Sealants ....... 6C -1 Exhaust System Requirements .
  • Page 327 Damage caused by water in the en- 1. Disconnect battery cables from battery. gine will not be covered by MerCruiser Warranty, unless this damage is the result of defective 2. Drain water from cylinder block, exhaust manifold part(s).

  • Page 328: Cleaning And Inspection

    IMPORTANT: If manifold to cylinder head studs WARNING have broken, install all new studs with Loctite Gasoline is extremely flammable and highly ex- 8831 AFTER checking head and manifold sur- faces for warpage. Also use all new manifold at- plosive under certain conditions. Be sure electri- taching nuts.
  • Page 329 4. Install exhaust elbow using new gasket. Torque to 5. Connect throttle cable to carburetor. Adjust as 25 lb. ft. (34 N·m). outlined in “Removal, Installation and Alignment.” IMPORTANT: Install gasket as shown. 6. Connect fuel line and electric choke wires. 7.
  • Page 330 3. Remove screws and lockwashers that secure WARNING lower exhaust pipe to gimbal housing. Be sure to read and follow package label direction when using Bellows Adhesive. 5. Replace shutter (in lower pipe), as shown. a. Coat both mating surfaces of hose and lower pipe with Bellows Adhesive.
  • Page 331 POWER STEERING 71317 PUMP Index...
  • Page 332 Table of Contents Page Page Torque Specifications ..... 7A-1 Power Steering Pump And Cooler ..7A-4 Tools/Sealants/Fluids .

  • Page 333: Torque Specifications

    Torque Specifications CAUTION Do not pry on power steering pump or alternator Fastener Location Lb. Ft. Lb. In. when adjusting belt tension. Serious damage Crankshaft Pulley to may result. Harmonic Balancer Harmonic Balancer to Crankshaft Checking Power Steering Pump Mounting Brack- Pump Fluid Level et to Engine Recirculation Pump...

  • Page 334: With Engine Warm From Operation

    4. If fluid level is low but still visble in pump reservoir, IMPORTANT: Use only Quicksilver Power Trim add fluid thru fill cap opening to bring level up to and Steering Fluid, or automatic transmission ”FULL COLD” mark on dipstick. Do not overfill. fluid (ATF), Dexron II, in power steering system.

  • Page 335: Pump Pulley Replacement

    b. Tighten retaining bolts. 4. While holding tool with suitable wrench, turn threaded screw until pulley is removed. 72821 74557 a - Kent-Moore Pulley Removal Tool (J-25034) a - Belt Deflection No More Than 1/4 Inch (6 mm) Maximum INSTALLATION 2.

  • Page 336: Power Steering Pump And Cooler

    Power Steering Pump And 3. Install 40 inch (1016 mm) drive belt. Cooler Replacment IMPORTANT: Refer to ”Precautions”, in this sec- tion BEFORE proceding. 1. Install pulley. 74564 a - 40 inch (1016 mm) Drive Belt 4. Install 37 inch (940 mm) drive belt over circulating pump pulley.
  • Page 337 5. Install front mount assembly with power steering 7. Attach power steering pump brace to pump. pump assembly. Tighten bolts securely. 74560 74558 a - 7/8 inch (22 mm) Long Bolt and Washer a - 2-3/4 inch (70 mm) Bolts, Washers and Lockwashers. 8.
  • Page 338 10. Route hydraulic hoses as shown. 11. DDIS AND EST MODELS: Install fluid cooler and tighten hose clamp-screw securely. 74569 a – Clamp-Screw, Tighten Securely 50629 12. BREAKER POINTS IGNITION MODELS: Install fluid cooler and tighten screw securely. DDIS Ignition a - Hydraulic Hose Routing 74585 a - 1 inch (25 mm) Bolts...

  • Page 339: Installation

    13. Install long water hose and tighten hose clamps INSTALLATION securely. 1. Using hose clamp, install new hose on back of pump. Tighten clamp securely. 72848 a - Hose Clamp b - Hose 74568 2. Using hose clamp, install hose on fluid cooler. Tighten clamp securely.

  • Page 340: Low Pressure Hose (Control Valve-To-Cooler)

    3. Fill and air bleed system. Refer to Section 1B - 2. Remove large fitting from control valve at tran- “Maintenance” (see “Table of Contents”). som. Remove hose. Low Pressure Hose (Control Valve-to-Cooler) REMOVAL NOTE: Catch fluid that drains from hose, cooler and pump in a suitable container.
  • Page 341 3. Thread large fitting into control valve. Position 5. Using hose clamp, install hose on fluid cooler. hose properly (as prior to removal). Tighten clamp securely. Earlier Style Control Valve: Torque large fitting to 20-25 lb. ft. (27-34 N·m). 72026 a - Large Fitting Later Style Control Valve: Torque fittings to 23 lb.

  • Page 342: Priority Valve Kit (79691A1) Information

    Priority Valve Kit (79691A1) 2. Position bottle reservoir in mounting bracket and secure with retainer spring. Information This kit information (in “Installation Instruction” form) is provided to assist personnel when servicing dual installations where both engines are equipped with power steering pumps, coolers, related hardware and hoses, and one transom assembly is equipped with power steering.

  • Page 343: Installing Priority Valve

    72856 a - Reservoir Cap b - Two-Way Valve (Installed) 4. Cut two hoses (from bulk hose supplied) of suffi- cient length to extend from bottom fittings on res- ervoir to fill caps on power steering pumps. Allow extra hose for routing. IMPORTANT: When routing and installing hoses in the following steps, be sure that the bend ra- 72858...
  • Page 344 b. Mount bracket using lag bolts and washers supplied. 72860 a - Bolt and Washer b - Washer and Nut (Not Shown in This View) c - Bracket 72859 d - Priority Valve a - Mounting Bracket NOTE: Engines with power steering are equipped b - Lag Bolts and Washers with a hose that is connected to the power steering NOTE: The 90 elbow locations on priority valve are...
  • Page 345 6. Connect one end of each hose to its respective 7. Install return hose (large fitting on one end only, power steering fluid cooler and other ends to fit- from kit) to power steering control valve. Route tings on priority valve. Secure with hose clamps. hose to priority valve, cut hose to length, and con- Tighten securely.
  • Page 346 8. Install pressure hose (fittings on both ends, from 9. Connect No. 1 (starboard) engine pressure hose kit) between power steering control valve and (from pump) to inverted flare fitting marked by “1” large inverted flare fitting on priority valve. (This on priority valve.

  • Page 347: Filling System With Fluid

    Filling System with Fluid Maintenance 11. Fill pump reservoirs with automatic transmission Maintenance inspection is the owner’s responsibility fluid (ATF) Dexron ll. and must be performed at the following intervals: 12. Install and tighten pump cap by turning cap clock- Normal Service - Every 50 hrs.

  • Page 348: System Flow Diagram

    System Flow Diagram Pressure Line Return Line Gravity Feed Line 72995 1 - Reservoir Bottle and Bracket 2 - Priority Valve and Mounting Bracket 3 - Power Steering Control Valve 4 - Power Steering Pump 5 - Power Steering Fluid Cooler a - Pressure Hose (Fitting on Both Ends - Supplied in Kit) b - Return Hose (Fitting on One End - Supplied in Kit) c - Return Hose from Pump (Cut from Bulk Hose Supplied)

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