Mercury FourStroke 2.5 Service Manual
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Mercury FourStroke 2.5 Service Manual

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2.5/3.5
FourStroke
Serial Number 0R448033 and Above

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Summary of Contents for Mercury FourStroke 2.5

  • Page 1 2.5/3.5 FourStroke Serial Number 0R448033 and Above...
  • Page 2 Manual Outline Important Information 1 - Important Information A - Master Specifications Electrical B - Maintenance C - General Information D - Outboard Installation Fuel System 2 - Electrical A - Ignition 3 - Fuel System Powerhead A - Carburetor and Fuel Pump B - Emissions 4 - Powerhead Midsection...
  • Page 3 NOTE: Indicates information that helps in the understanding of a particular step or action. This manual has been written and published by the Service Department of Mercury Marine to aid our dealers’ mechanics and company service personnel when servicing the products described herein. We reserve the right to make changes to this manual without prior notification.
  • Page 4 Cleanliness and Care of Product A Mercury Marine Power Product is a combination of many machined, honed, polished, and lapped surfaces with tolerances measured in the ten thousands of an inch/mm. When any product component is serviced, care and cleanliness are important. It should be understood that proper cleaning and protection of machined surfaces and friction areas is a part of the repair procedure.
  • Page 5 Page iv...

  • Page 6: Table Of Contents

    Master Specifications Important Information Section 1A - Master Specifications Table of Contents Model Specifications............1A-2 Piston Specifications............1A-5 Ignition Specifications............1A-2 Camshaft and Valve Specifications........1A-6 Carburetor Specifications...........1A-3 Gear Housing Specifications..........1A-6 Cooling System Specifications...........1A-3 Propellers................1A-7 Cylinder Block Specifications..........1A-4 90-8M0065421 NOVEMBER 2012 Page 1A-1...

  • Page 7: Model Specifications

    Master Specifications Model Specifications Model Specifications 1.9 kW (2.5 hp) Power 2.6 kW (3.5 hp) Weight (2.5 models) 17 kg (38 lb) 18 kg (40 lb) Weight (3.5 models) 17 kg (38 lb) 18 kg (40 lb) Recommended RPM range at WOT (3.5 models) 5000–6000 RPM Recommended RPM range at WOT (2.5 models) 4500–5500 RPM...

  • Page 8: Carburetor Specifications

    Master Specifications Carburetor Specifications Carburetor Specifications 2.5 HP Venturi 9 mm (0.35 in.) Throttle bore 16 mm (0.63 in.) Main jet Main nozzle I.D. 1.4 mm (0.06 in.) Slow jet Idle air jet #115 Idle speed (neutral) 1400 ± 50 RPM Idle speed (forward) 1300 ±...

  • Page 9: Cylinder Block Specifications

    Master Specifications Cylinder Block Specifications Cylinder Block Specifications Cylinder bore Standard 55 mm (2.1653 in.) Oversize 55.5 mm (2.1850 in.) Maximum taper/out of round 0.06 mm (0.0024 in.) Stroke 36 mm (1.42 in.) Displacement 85.5 ml (5.22 in.³) Number of cylinders Rotation Clockwise Crankshaft...

  • Page 10: Piston Specifications

    Master Specifications Piston Specifications Piston Specifications Piston outside diameter (standard) 54.96 mm (2.1638 in.) Piston outside diameter (service limit) 54.90 mm (2.1614 in.) Piston clearance (standard) 0.020–0.06 mm (0.0008–0.0024 in.) Piston clearance (service limit) 0.15 mm (0.0059 in.) Piston ring side clearance (standard) 0.04–0.08 mm (0.0016–0.0031 in.) Middle 0.03–0.07 mm (0.0012–0.0028 in.)

  • Page 11: Camshaft And Valve Specifications

    Master Specifications Camshaft and Valve Specifications Camshaft and Valve Specifications Camshaft Runout limit 0.03 mm (0.0012 in.) Cam lobe height (intake and exhaust) 23.78–24.04 mm (0.94–0.95 in.) Upper bearing O.D. 11.95–11.97 mm (0.4705–0.4713 in.) Lower bearing O.D. 12.95–12.97 mm (0.5098–0.5106 in.) Valve spring free length 33.2–35.0 mm (1.307–1.378 in.) Valve spring tilt limit...

  • Page 12: Propellers

    Master Specifications Propellers Propellers Standard (plastic) 7.4 dia. x 7 pitch Optional (aluminum) 7.4 dia. x 5.7 pitch Optional (plastic) 7.4 dia. x 5.7 pitch 90-8M0065421 NOVEMBER 2012 Page 1A-7...
  • Page 13 Master Specifications Notes: Page 1A-8 90-8M0065421 NOVEMBER 2012...
  • Page 14 Maintenance Important Information Section 1B - Maintenance Table of Contents EPA Emission Regulations..........1B-2 Changing Engine Oil ............1B-5 Emission Certification Label........1B-2 Engine Oil Capacity............ 1B-5 Owner Responsibility..........1B-2 Oil Changing Procedure..........1B-5 Selecting Accessories for Your Outboard......1B-2 Oil Filling..............

  • Page 15: Epa Emission Regulations

    Some accessories not manufactured or sold by Mercury Marine are not designed to be safely used with your outboard or outboard operating system. Acquire and read the installation, operation and maintenance manuals for all your selected accessories.

  • Page 16: After Each Use

    Flush the internal water passages of the outboard with fresh water after each use in salt, polluted, or muddy water. This will help prevent a buildup of deposits from clogging the internal water passages. Use a Mercury Precision or Quicksilver accessory (or equivalent) flushing attachment. NOTE: Do not run the engine while flushing the cooling system.

  • Page 17: Top Cowl Removal And Installation

    We recommend the use of Mercury or Quicksilver SAE 10W‑30 multi‑viscosity 4‑Stroke Outboard Oil for general, all‑temperature use. If SAE 25W‑40 multi‑viscosity oil is preferred, use Mercury MerCruiser 4‑cycle engine oil or Quicksilver sterndrive and inboard 4‑cycle engine oil. Never use 4‑cycle engine oil that is not certified to meet or exceed any one or combination of the following American Petroleum Institute (API) Service Classification SH, SG, SF, CF‑4, CE, CD, CDII.

  • Page 18: Checking Engine Oil

    Maintenance Checking Engine Oil IMPORTANT: Do not overfill. Be sure that the outboard is upright (not tilted) when checking oil. Position the outboard so it is sitting level. Verify the oil level through the oil level inspection window. If the oil level is down toward the lower level mark, remove the oil fill cap, and fill up to the upper level mark.

  • Page 19: Spark Plug Inspection And Replacement

    Maintenance Spark Plug Inspection and Replacement WARNING Damaged spark plug boots may emit sparks which can ignite fuel vapors under the engine cowl, resulting in serious injury or death from a fire or explosion. To avoid damaging the spark plug boots, do not use any sharp object or metal tool to remove the spark plug boots.

  • Page 20: Propeller Replacement

    Maintenance The anode requires periodic inspection especially in saltwater which will accelerate the erosion. To maintain this corrosion protection, always replace the anode before it is completely eroded. Never paint or apply a protective coating on the anode as this will reduce effectiveness of the anode. 28709 Propeller Replacement WARNING...

  • Page 21: Gearcase Lubrication

    Maintenance Pull the propeller straight off the shaft. Retain the drive pin. If the propeller is seized to the shaft and cannot be removed, have the propeller removed by an authorized dealer. Drive pin 19022 Insert the drive pin into the propeller shaft. Drive pin 19023 Slide the propeller onto the shaft, making sure the slot in the propeller engages with the drive pin.

  • Page 22: Gearcase Lubricant Capacity

    Stop adding lubricant. Use new sealing washer and install the vent plug before removing the lubricant tube. Remove lubricant tube and reinstall cleaned fill/drain plug and new sealing washer. Lubrication Points Lubricate the following with Quicksilver or Mercury Precision Lubricants 2‑4‑C with PTFE or Special Lubricant 101. Tube Ref No. Description Where Used Part No.

  • Page 23: Storage Preparation

    Maintenance • Steering friction knob ‑ lubricate threads. 19231 • Tilt support pin ‑ lubricate pin • Transom clamp screws ‑ lubricate threads • Tilt pivot point ‑ lubricate with lightweight oil Tilt support pin Tilt pivot point Transom clamp screws 19233 •...

  • Page 24: Protecting External Outboard Components

    Lubricate all outboard components listed in Maintenance ‑ Inspection and Maintenance Schedule. • Touch up any paint nicks. See your dealer for touch‑up paint. • Spray Quicksilver or Mercury Precision Lubricants Corrosion Guard on external metal surfaces (except corrosion control anodes). Tube Ref No. Description Where Used Part No.
  • Page 25 Maintenance Notes: Page 1B-12 90-8M0065421 NOVEMBER 2012...
  • Page 26 General Information Important Information Section 1C - General Information Table of Contents Component Identification........... 1C-2 Saltwater Submersion (Special Instructions)....1C-8 2/2.5/3.5 FourStroke Front View.........1C-2 Fresh Water Submersion (Special Instructions)..1C-8 2/2.5/3.5 FourStroke Starboard View......1C-3 Compression Check........... 1C-9 2/2.5/3.5 FourStroke Aft View........1C-4 Cylinder Leakage Testing...........1C-9 2/2.5/3.5 FourStroke Port View........

  • Page 27: Component Identification

    General Information Special Tools Cylinder Leakage Tester Snap‑On EEPV309A Aids in checking cylinder leakdown. 11604 Component Identification 2/2.5/3.5 FourStroke Front View Fuel cap vent Fuel cap Fuel tank Recoil starter handle Fuel pump Stop switch with lanyard Carry handle Model decal Tilt stopper Choke knob Shift lever...

  • Page 28: 2/2.5/3.5 Fourstroke Starboard View

    General Information 2/2.5/3.5 FourStroke Starboard View 49955 Recoil starter Recoil starter handle Throttle grip Throttle friction knob Shift lever Clamp handle Clamp bracket Choke cable Oil fill cap Oil level sight window Fuel tank on/off valve Steering friction knob Oil drain plug Carburetor vent hoses Bottom cowl Rear cowl latch...

  • Page 29: 2/2.5/3.5 Fourstroke Aft View

    General Information 2/2.5/3.5 FourStroke Aft View Fuel cap vent Fuel cap Fuel tank Rear cowl latch Water pump indicator hose Steering friction knob Spark plug boot Throttle cables Tiller handle Cylinder head cover 49956 Page 1C-4 90-8M0065421 NOVEMBER 2012...

  • Page 30: 2/2.5/3.5 Fourstroke Port View

    General Information 2/2.5/3.5 FourStroke Port View High tension lead Spark plug Fuel pump pulse hose Water pump indicator hose Steering friction knob Tiller handle Flywheel cover Fuel pump Throttle cables 49957 90-8M0065421 NOVEMBER 2012 Page 1C-5...

  • Page 31: 2/2.5/3.5 Fourstroke Top View

    30% relative humidity, at 25 °C (77 °F) temperature, and a barometric pressure of 29.61 inches of mercury. Summer conditions of high temperature, low barometric pressure, and high humidity all combine to reduce the engine power.

  • Page 32: Weight Distribution (Passengers And Gear) Inside The Boat

    General Information Weight Distribution (Passengers and Gear) Inside the Boat Shifting weight to rear (stern): • Generally increases speed and engine RPM • Causes bow to bounce in choppy water • Increases danger of following wave splashing into the boat when coming off plane •...

  • Page 33: Propeller Selection

    The boat manufacturer and the selling dealer are responsible for equipping the power package with the correct propeller. Refer to Mercury Marine's web page http://www.mercurymarine.com for information. Select a propeller that will allow the engine power package to operate at or near the top end of the recommended WOT operating RPM range with a normal load.

  • Page 34: Compression Check

    Clean the surface to be painted using PPG Industries DX330 Wax and Grease Remover or equivalent (Xylene or M.E.K.). If bare metal has been exposed, use Mercury/Quicksilver Light Gray Primer. Allow a minimum of one hour dry time and no more than one week before applying the finish coat.

  • Page 35: Gear Housing

    Allow a minimum of one hour drying time and no more than one week before the top coat application. Use Ditzler Urethane DU9300 for Mercury Black, DU34334 for Mariner Grey, DU35466 for Force Charcoal, DU33414M for Sea Ray White, and DFHS 37372H for Verado Silver. Catalyze all five colors with Ditzler DU5 catalyst mixed 1:1 ratio.

  • Page 36: Decal Application

    General Information Saturate a clean paper towel with the isopropyl alcohol and water solution. Wipe the cowl with the saturated towel followed immediately with a lint‑free towel before the solution evaporates. NOTE: Isopropyl alcohol evaporates quickly. You must wipe the surface immediately after applying the solution. When the paper towel becomes contaminated with dirt, discard it and use a clean paper towel saturated with the isopropyl alcohol and water solution.

  • Page 37: Entrapped Air Removal

    General Information IMPORTANT: When the premask is removed from the decal, the pulling force loosens the adhesive at the edges of the decal. It is imperative to squeegee the entire decal with special attention to the edges of the decal. 50338 11.
  • Page 38 Outboard Installation Important Information Section 1D - Outboard Installation Table of Contents Boat Horsepower Capacity..........1D-2 Installing the Outboard on the Transom..... 1D-2 Selecting Accessories for Your Outboard......1D-2 Tilt Pin Adjustment............1D-3 Installing the Outboard............1D-2 Engine Overspeed Protection System......1D-3 Boat Transom Height Requirement......1D-2 Installation Drawings..........

  • Page 39: Boat Horsepower Capacity

    Some accessories not manufactured or sold by Mercury Marine are not designed to be safely used with your outboard or outboard operating system. Acquire and read the installation, operation and maintenance manuals for all your selected accessories.

  • Page 40: Tilt Pin Adjustment

    Outboard Installation Tighten the transom clamp handles. 19057 Tilt Pin Adjustment The vertical operating angle of the outboard is adjusted by changing the position of the tilt pin in the adjustment holes provided. Proper adjustment allows the boat to run stable, achieve optimum performance, and minimize steering effort. The tilt pin should be adjusted so the outboard is positioned to run perpendicular to the water when the boat is running at full speed.

  • Page 41: Installation Drawings

    Outboard Installation Installation Drawings 377 mm (14.8 in.) Short shaft ‑ 649 mm (25.5 in.); long shaft ‑ 776 mm (30.6 in.) Short shaft ‑ 434 mm (17.1 in.); long shaft ‑ 561 mm (22.1 in.) 446 mm (17.6 in.) 108 mm (4.3 in.) 358 mm (14.1 in.) 336 mm (13.2 in.)
  • Page 42 Ignition Electrical Section 2A - Ignition Table of Contents Ignition Specifications............2A-2 Ignition Coil Replacement..........2A-8 Flywheel and Ignition Components........2A-4 Removal..............2A-8 Ignition System Description..........2A-6 Installation..............2A-9 Flywheel Removal and Installation........2A-6 Ignition Coil Testing............2A-11 Removal..............2A-6 Secondary Resistance..........2A-11 Installation..............2A-7 Checking Ignition Timing..........2A-12 90-8M0065421 NOVEMBER 2012 Page 2A-1...

  • Page 43: Ignition Specifications

    Ignition Ignition Specifications Ignition Specifications at 20 °C (68 °F) Ignition type Digital capacitor discharge ignition Spark plug type NGK DPR6E Spark plug gap 0.8–0.9 mm (0.031–0.035 in.) Ignition timing at idle 3° ± 3° BTDC Ignition timing at WOT 25°...
  • Page 44 Ignition Notes: 90-8M0065421 NOVEMBER 2012 Page 2A-3...

  • Page 45: Flywheel And Ignition Components

    Ignition Flywheel and Ignition Components 42489 Page 2A-4 90-8M0065421 NOVEMBER 2012...
  • Page 46 Ignition Flywheel and Ignition Components Torque Ref. No. Qty. Description lb‑in. lb‑ft Flywheel Flywheel cover Collar Washer Ignition coil Spark plug lead Bolt (M6 x 20) Stop switch Lanyard 90-8M0065421 NOVEMBER 2012 Page 2A-5...

  • Page 47: Ignition System Description

    Ignition Ignition System Description A single digital capacitor discharge ignition (CDI) coil is utilized on this model. Major components of this system are the flywheel, ignition coil, and the spark plug. A stop switch is provided which shorts the ignition coil to ground preventing spark. Flywheel Removal and Installation Removal WARNING...

  • Page 48: Installation

    Ignition Puller Set FT8948‑1 Description lb‑in. lb‑ft Flywheel puller bolts Installation Install the flywheel key into the crankshaft keyway. Crankshaft Flywheel key 49996 Align the flywheel keyway with the key. Install the flywheel onto the crankshaft. Ensure the flywheel is fully seated on the crankshaft taper.

  • Page 49: Ignition Coil Replacement

    Ignition Install the flywheel cover. Flywheel Cover Flywheel nut 49994 Install the recoil starter and fuel tank. Refer to Section 8A ‑ Recoil Starter. Connect the spark plug lead to the spark plug. Ignition Coil Replacement Removal WARNING Fuel is flammable and explosive. Ensure that the key switch is off and the lanyard is positioned so that the engine cannot start.

  • Page 50: Installation

    Ignition Remove the recoil starter and flywheel cover. Recoil starter Flywheel cover J‑clip Bolt and washer (M6 x 60) (3) 49999 Disconnect the stop switch tan wire connector. Remove the two ignition coil mounting bolts. Ignition coil mounting bolts (M6 x 20) (2) Ignition coil J‑clamp Spark plug lead...
  • Page 51 Ignition Ignition Specification Ignition coil gap 0.3 mm (0.012 in.) Tighten the two ignition coil mounting bolts to the specified torque. Install the spark plug lead onto the spark plug and secure with the J‑clamp. Connect the stop switch tan wire connector. Ignition coil mounting bolts (M6 x 20) (2) Ignition coil J‑clamp...

  • Page 52: Ignition Coil Testing

    Ignition 11. Apply Loctite 242 Threadlocker to the three fuel tank mounting bolts. Install the bolts and washers. Tighten the bolts to the specified torque. Fuel tank Bolt and washer (M6 x 25) (3) 50010 Tube Ref No. Description Where Used Part No.

  • Page 53: Checking Ignition Timing

    Ignition Meter Test Leads Meter Scale Reading (kΩ) Black Spark plug lead Black ground wire Ω 10.7–15.7 If the reading is other than specified, replace the ignition coil. Refer to Ignition coil Replacement. Checking Ignition Timing WARNING Moving parts can cause serious injury or death. Wear eye protection and keep hands, hair, and clothing away from moving parts when performing tests or checking adjustments on an operating engine.
  • Page 54 Carburetor and Fuel Pump Fuel System Section 3A - Carburetor and Fuel Pump Table of Contents Carburetor Specifications...........3A-2 Fuel Pump Hoses............. 3A-10 Carburetor Components............ 3A-4 Installation..............3A-10 Fuel Tank Components............3A-6 Carburetor Removal and Installation....... 3A-11 Carburetor Adjustments............. 3A-8 Removal..............3A-11 Pilot (Idle Mixture) Screw..........3A-8 Installation..............3A-12 Idle Speed..............3A-8 Carburetor Disassembly..........

  • Page 55: Carburetor Specifications

    Carburetor and Fuel Pump Carburetor Specifications Carburetor Specifications 2.5 HP Venturi 9 mm (0.35 in.) Throttle bore 16 mm (0.63 in.) Main jet Main nozzle I.D. 1.4 mm (0.06 in.) Slow jet Idle air jet #115 Idle speed (neutral) 1400 ± 50 RPM Idle speed (forward) 1300 ±...
  • Page 56 Carburetor and Fuel Pump Notes: 90-8M0065421 NOVEMBER 2012 Page 3A-3...

  • Page 57: Carburetor Components

    Carburetor and Fuel Pump Carburetor Components 51317 Page 3A-4 90-8M0065421 NOVEMBER 2012...
  • Page 58 Carburetor and Fuel Pump Carburetor Components Torque Ref. No. Qty. Description lb‑in. lb‑ft Carburetor Idle speed screw Spring Pilot jet Pilot mixture screw, spring, and tamperproof plug Rubber plug Main nozzle Main jet Float valve Clip Float Float pin Float bowl Gasket Drain screw (M5 x 6) O‑ring...

  • Page 59: Fuel Tank Components

    Carburetor and Fuel Pump Fuel Tank Components 51309 Page 3A-6 90-8M0065421 NOVEMBER 2012...
  • Page 60 Carburetor and Fuel Pump Fuel Tank Components Torque Ref. No. Qty. Description lb‑in. lb‑ft Fuel tank Cover Spacer Washer Bolt Seal Caution decal Fuel cap Gasket Hook Fuel hose to fuel pump inlet Clip Fuel valve Rubber seal O‑ring Fuel valve knob Clip Fuel hose Clip...

  • Page 61: Carburetor Adjustments

    Carburetor and Fuel Pump Carburetor Adjustments Pilot (Idle Mixture) Screw IMPORTANT: The pilot mixture screw is set at the factory to allow the engine to meet established government emission specifications. The pilot mixture screw is normally hidden with a tamperproof plug. However, if the carburetor requires rebuilding and/or cleaning, the plug can be removed and the pilot mixture screw removed to facilitate cleaning.

  • Page 62: Fuel Pump Removal And Installation

    Carburetor and Fuel Pump Fuel Pump Removal and Installation WARNING Fuel is flammable and explosive. Ensure that the key switch is off and the lanyard is positioned so that the engine cannot start. Do not smoke or allow sources of spark or open flame in the area while servicing. Keep the work area well ventilated and avoid prolonged exposure to vapors.

  • Page 63: Fuel Pump Hoses

    Carburetor and Fuel Pump Remove the three fuel hoses. Wipe up any spilled fuel immediately. 50026 Thermostat housing bracket Bolt (M6 x 30) (2) Fuel pump Pulse hose Fuel pump inlet hose Fuel pump outlet hose Fuel Pump Hoses Fuel pump Bolt (M6 x 30) (2) Thermostat housing bracket Pulse hose to intake manifold fitting...

  • Page 64: Carburetor Removal And Installation

    Carburetor and Fuel Pump Carburetor Removal and Installation Removal With the outboard in water, close the fuel valve and run the engine until it stops. This will empty the fuel from the carburetor. Open position Closed position Fuel valve arrow 41665 Close the fuel tank vent after the engine has stopped.

  • Page 65: Installation

    Carburetor and Fuel Pump Disconnect the choke cable and the throttle linkage from the carburetor. Remove the carburetor from the engine. Crankcase breather hose Throttle linkage Vent hose (1 of 2) Choke cable Carburetor/air silencer bolt (M6 x 85) (2) 41668 Installation Connect the choke cable and the throttle linkage to the carburetor.
  • Page 66 Carburetor and Fuel Pump Secure the air silencer and carburetor to the intake manifold with two bolts, washers, and collars. Tighten the bolts to the specified torque. 41735 Fuel hose Crankcase breather hose Bolt (M6 x 85) (2) Flat washer (2) Collar (2) Choke cable Air silencer...
  • Page 67 Carburetor and Fuel Pump Tighten the choke cable holder bolt and the throttle opener bolt to the specified torque. 49876 Throttle opener Throttle opener bolt Throttle rod Choke wire Choke cable holder bolt Carburetor mounting bolt (2) Gasket (2) Insulator Description lb‑in.
  • Page 68 Carburetor and Fuel Pump 11. Secure the choke cable with the J‑clamp and the washer and bolt. J‑clamp Washer and bolt securing choke cable Fuel pump inlet hose Fuel shutoff valve Fuel shutoff valve knob Fuel pump outlet hose Bracket 49878 12.

  • Page 69: Carburetor Disassembly

    Carburetor and Fuel Pump 13. Install the fuel tank onto the engine. Secure the fuel tank with three bolts and washers. Tighten the bolts to the specified torque. Fuel tank Bolts and washers 50010 Description lb‑in. lb‑ft Fuel tank bolts Carburetor Disassembly Remove the drain screw and drain the carburetor before disassembly.
  • Page 70 Carburetor and Fuel Pump Remove the pilot jet. 50771 Remove the pilot mixture screw. Remove the tamperproof plug. Count and record the number of revolutions to lightly seat the pilot mixture screw. IMPORTANT: This information will be used during carburetor assembly. Remove the pilot mixture screw and spring.
  • Page 71 Carburetor and Fuel Pump Push out the float pin in the direction shown. Remove the float and the inlet needle. 50773 Knurled end of the float pin Float Inlet needle Remove the rubber plug. Remove the main jet. Remove the main nozzle. The nozzle should drop out. If not, carefully push the nozzle out as shown. 50774 Main jet Main nozzle...

  • Page 72: Inspection

    Carburetor and Fuel Pump Inspection Clean the main jet, main nozzle, and pilot jet with a suitable solvent. Dry all components thoroughly with compressed air before installation. Main nozzle Main jet Pilot jet 50775 Inspect the tip of the inlet needle and pilot mixture screw for wear. Inlet needle Pilot mixture screw 50776...

  • Page 73: Carburetor Assembly

    Carburetor and Fuel Pump Clean the carburetor body, float bowl, and components in an ultrasonic cleaner. Follow the instructions of the manufacturer. Carburetor Assembly Install the inlet needle assembly onto the float arm. Install the float. Push in the float pin in the direction of the arrow. 50779 Inlet needle assembly Float...
  • Page 74 Carburetor and Fuel Pump Install the pilot jet. 50771 Install the pilot mixture spring and screw. Turn the pilot mixture screw until it is seated. Then back the screw out the same number of turns as measured during removal. Install a tamperproof plug. Refer to the parts manual for the part number. 50772 Tamperproof plug Pilot mixture screw...
  • Page 75 Carburetor and Fuel Pump Install the rubber plug. Main jet Main nozzle Rubber plug 50854 10. Install the carburetor drain screw. 11. Install the O‑ring gasket onto the float bowl. 12. Install the float bowl. Tighten the screws to the specified torque. Float bowl Screw (M4 x 12) (2) Drain screw...
  • Page 76 Emissions Fuel System Section 3B - Emissions Table of Contents Exhaust Emission Standards..........3B-2 Dealer Responsibility..........3B-3 What Are Emissions?..........3B-2 Owner Responsibility..........3B-3 Hydrocarbons (HC).............3B-2 Exceptions..............3B-3 Carbon Monoxide (CO)..........3B-2 EPA Emission Regulations......... 3B-3 Oxides of Nitrogen (NOx)........... 3B-2 Manufacturer's Certificate Label........
  • Page 77 Emissions Exhaust Emission Standards Through the Environmental Protection Agency (EPA), the federal government has established exhaust emission standards for all new marine engines sold in the U.S. What Are Emissions? Emissions are what comes out of the exhaust system in the exhaust gas when the engine is running. They are formed as a result of the process of combustion or incomplete combustion.
  • Page 78 EPA Emission Regulations All 1998 and newer outboards manufactured by Mercury Marine are certified to the United States Environmental Protection Agency as conforming to the requirements of the regulations for the control of air pollution from new outboard motors. This certification is contingent on certain adjustments being set to factory standards.
  • Page 79 Service Replacement Certification Label IMPORTANT: By federal law, it is required that all 1998 and newer Mercury Marine outboards have a visible and legible emission certification label. If this label is missing or damaged, contact Mercury Marine Service for a replacement.
  • Page 80 Cut and remove a "V" notch through the month of engine manufacture before installing the new label. The month of manufacture can be found on the old label. If the label is missing or the date code illegible, contact Mercury Marine Technical Service for assistance.
  • Page 81 Emissions Notes: Page 3B-6 90-8M0065421 NOVEMBER 2012...
  • Page 82 Powerhead Powerhead Section 4A - Powerhead Table of Contents Camshaft and Valve Specifications........4A-2 Piston................4A-25 Cooling System Specifications...........4A-2 Piston Pin..............4A-26 Piston Specifications............4A-3 Piston Rings..............4A-27 Cylinder Block Specifications..........4A-4 Connecting Rod............4A-28 Camshaft and Valve Components........4A-6 Crankshaft..............4A-28 Crankshaft, Piston, and Connecting Rod Components..4A-8 Inspecting the Camshaft and Valves.......

  • Page 83: Camshaft And Valve Specifications

    Powerhead Camshaft and Valve Specifications Camshaft and Valve Specifications Camshaft Runout limit 0.03 mm (0.0012 in.) Cam lobe height (intake and exhaust) 23.78–24.04 mm (0.94–0.95 in.) Upper bearing O.D. 11.95–11.97 mm (0.4705–0.4713 in.) Lower bearing O.D. 12.95–12.97 mm (0.5098–0.5106 in.) Valve spring free length 33.2–35.0 mm (1.307–1.378 in.) Valve spring tilt limit...

  • Page 84: Piston Specifications

    Powerhead Piston Specifications Piston Specifications Piston outside diameter (standard) 54.96 mm (2.1638 in.) Piston outside diameter (service limit) 54.90 mm (2.1614 in.) Piston clearance (standard) 0.020–0.06 mm (0.0008–0.0024 in.) Piston clearance (service limit) 0.15 mm (0.0059 in.) Piston ring side clearance (standard) 0.04–0.08 mm (0.0016–0.0031 in.) Middle 0.03–0.07 mm (0.0012–0.0028 in.)

  • Page 85: Cylinder Block Specifications

    Powerhead Cylinder Block Specifications Cylinder Block Specifications Cylinder bore Standard 55 mm (2.1653 in.) Oversize 55.5 mm (2.1850 in.) Maximum taper/out of round 0.06 mm (0.0024 in.) Stroke 36 mm (1.42 in.) Displacement 85.5 ml (5.22 in.³) Number of cylinders Rotation Clockwise Crankshaft...
  • Page 86 Powerhead Piston Ring Expander 91‑24697 Expands piston rings for removal and installation 6255 Bearing Puller Assembly 91‑83165T Removes bearings, races and bearing carriers 3610 90-8M0065421 NOVEMBER 2012 Page 4A-5...

  • Page 87: Camshaft And Valve Components

    Powerhead Camshaft and Valve Components 22493 Page 4A-6 90-8M0065421 NOVEMBER 2012...
  • Page 88 Powerhead Camshaft and Valve Components Torque Ref. No. Qty. Description lb‑in. lb‑ft Camshaft assembly Intake valve Exhaust valve Intake seal (black) Exhaust seal (green) Seat Spring Retainer Keeper Lifter Push rod Push rod plate Pivot bolt 19.2 Rocker arm Pivot 90-8M0065421 NOVEMBER 2012 Page 4A-7...

  • Page 89: Crankshaft, Piston, And Connecting Rod Components

    Powerhead Crankshaft, Piston, and Connecting Rod Components 41756 Page 4A-8 90-8M0065421 NOVEMBER 2012...
  • Page 90 Powerhead Crankshaft, Piston, and Connecting Rod Components Torque Ref. No. Qty. Description lb‑in. lb‑ft Crankshaft assembly Ball bearing Oil seal Connecting rod assembly First torque Screw Final torque Piston pin Clip Piston assembly Ring set Second piston ring Oil ring assembly 90-8M0065421 NOVEMBER 2012 Page 4A-9...

  • Page 91: Oil Pan Components

    Powerhead Oil Pan Components 17 16 22492 Page 4A-10 90-8M0065421 NOVEMBER 2012...
  • Page 92 Powerhead Oil Pan Components Torque Ref. No. Qty. Description lb‑in. lb‑ft Oil pan Oil level sight gauge Dowel pin Drain bolt Washer Bolt (M6 x 35) Oil seal O‑ring Oil seal Driveshaft seal housing Bolt (M6 x 20) Oil pan gasket Oil filler cap O‑ring Bolt (M6 x 20)

  • Page 93: Cylinder Block Components

    Powerhead Cylinder Block Components 50918 Page 4A-12 90-8M0065421 NOVEMBER 2012...
  • Page 94 Powerhead Cylinder Block Components Torque Ref. No. Qty. Description lb‑in. lb‑ft Cylinder block Dowel pin Bolt (M6 x 35) Bolt (M6 x 75) Washer Recommended oil decal Cylinder head cover Cylinder head cover gasket Bolt (M6 x 16) Washer Thermostat Thermostat cap Thermostat cap gasket Clamp...

  • Page 95: Thermostat

    Powerhead Thermostat Removal Close the manual vent screw on the fuel cap. Fuel cap Manual vent screw 47368 Remove the three bolts securing the fuel tank and move the fuel tank to the side. Fuel tank Bolt (M6 x 25) and washer 50010 Straighten the J‑clamp securing the throttle cables.

  • Page 96: Inspection

    Powerhead Move the thermostat housing bracket with the fuel pump to the side. 50007 Thermostat cap Fuel pump pulse hose Bolts (M6 x 30) (2) J‑clamp Fuel pump Bolt (M6 x 60) Remove the gasket and thermostat. Thermostat Gasket 50008 Inspection Tie a piece of thread or other nonconductive material onto the thermostat.

  • Page 97: Installation

    Powerhead Measure the thermostat opening when the specified water temperature is achieved. 3120 Minimum thermostat valve lift Thermostat Specifications Start to open temperature 50–54 °C (122–129 °F) Full open temperature 60–64 °C (140–147 °F) Minimum thermostat valve lift 2 mm (0.079 in.) Installation Clean the gasket surfaces on the thermostat housing bracket and cylinder block.
  • Page 98 Powerhead Install the fuel pump pulse hose to the intake manifold fitting. Secure the hose with a hose clamp. 50007 Thermostat cap Fuel pump pulse hose Bolts (M6 x 30) (2) J‑clamp Fuel pump Bolt (M6 x 60) Install the fuel tank assembly. Attach the fuel line to the fuel tank and secure it with a hose clamp. WARNING Fuel is flammable and explosive.

  • Page 99: Valve Clearance Adjustment

    Powerhead Description lb‑in. lb‑ft Fuel tank mounting bolts (M6 x 25) (3) Valve Clearance Adjustment IMPORTANT: Adjust the valve clearance while the engine temperature is cool. Align the timing mark on the flywheel to 0° TDC on the compression stroke. The piston is at top dead center and both valves are closed.

  • Page 100: Powerhead Removal

    Powerhead Description lb‑in. lb‑ft Cylinder head cover bolts (M6 x 16) (4) Install the spark plug lead to the spark plug. Secure the spark plug lead with the J‑clamp. Powerhead Removal Drain the engine oil. Remove the fuel tank and recoil starter. Refer to Section 8A ‑ Recoil Starter. Remove the fuel pump pulse hose from the intake manifold.

  • Page 101: Powerhead Disassembly

    Powerhead Powerhead Disassembly Oil Pan Removal Remove the oil sight gauge hose. Remove the fuel shutoff valve/hose assembly. Remove the fuel shutoff valve bracket. Oil sight gauge hose Fuel pump inlet hose Fuel shutoff valve Fuel shutoff valve bracket Bolt (M6 x 20) with washer Fuel tank outlet hose 50014 Remove the hoses from the fuel pump.

  • Page 102: Cylinder Block Disassembly

    Powerhead Remove the bolts securing the driveshaft seal housing. Driveshaft seal housing bolts (M6 x 20) (2) Oil pan bolts (M6 x 35) (8) Pry point 41751 Cylinder Block Disassembly Remove the seven bolts securing the two cylinder block housings and separate the cylinder block housings. 26589 Remove the camshaft/gear assembly from the cylinder block.

  • Page 103: Crankshaft/Piston Disassembly

    Powerhead Crankshaft/Piston Disassembly Remove the two bolts from the connecting rod cap. Remove the piston assembly from the crankshaft. Remove the upper bearing on the crankshaft using a universal puller plate. NOTE: The lower bearing and gear are not serviceable. Connecting rod cap bolts Upper bearing 26600...

  • Page 104: Valve Lifter/Rocker Arm Disassembly

    Powerhead Valve Lifter/Rocker Arm Disassembly Remove the valve lifters and push rods. Valve lifter and push rod Cylinder block 26672 Remove the cylinder head cover. Remove the gasket. Clean the gasket surface on the cylinder head cover and the cylinder block. Cylinder head cover Bolt and washer (M6 x 16) (4) 26673...

  • Page 105: Cleaning/Inspection/Repair

    Powerhead NOTE: Hold the valves in place from the cylinder bore end during the disassembly procedure. 26675 Remove the valve keepers, valve spring retainer, spring, and spring seat. Remove the intake and exhaust valves. 10. Remove the intake and exhaust valve seals. Exhaust valve seal (green) Intake valve seal (black) 26676...

  • Page 106: Cylinder Bore Measurement

    Powerhead Ensure the flywheel magnet is secured to the flywheel. Keyway Magnet 42585 Cylinder Bore Measurement Inspect the water jacket areas for mineral deposit and blockage. Clean the water jacket area as needed. Inspect the surface of the cylinder bores. Deep scoring will require the cylinder block to be bored oversize and finished honed.

  • Page 107: Piston Pin

    Powerhead Piston Outside diameter (standard) 54.96 mm (2.1638 in.) Outside diameter (service limit) 54.90 mm (2.1614 in.) Clearance (standard) 0.02–0.06 mm (0.00078–0.00236 in.) Clearance (service limit) 0.15 mm (0.0059 in.) To determine a piston to cylinder wall clearance, use this formula: •...

  • Page 108: Piston Rings

    Powerhead Piston Rings Piston Ring Side Clearance Measure the piston ring side clearance and replace the piston or rings if out of specification. 3136 Piston Ring Side Clearance (Standard) 0.04–0.08 mm (0.0016–0.0031 in.) Middle 0.03–0.07 mm (0.0012–0.00276 in.) Bottom 0.05–0.15 mm (0.002–0.0059 in.) Piston Ring Side Clearance (Service Limit) 0.10 mm (0.0039 in.) Middle...

  • Page 109: Connecting Rod

    Powerhead Piston Ring End Gap (Standard) 0.15–0.30 mm (0.0059–0.0118 in.) Middle 0.30–0.45 mm (0.0118–0.0177 in.) Bottom 0.20–0.70 mm (0.0079–0.0276 in.) Piston Ring End Gap (Service Limit) 0.5 mm (0.0197 in.) Middle 0.7 mm (0.0276 in.) Connecting Rod Measure the small end inside diameter of the connecting rod. 26699 Connecting rod Wrist pin diameter (standard)
  • Page 110 Powerhead Replace the crankshaft if the journal is out of specification. Crankpin journal diameter 26639 Crankshaft Bearing Journal Crankpin journal (standard) 19.98 mm (0.7866 in.) Crankpin journal (service limit) 19.95 mm (0.7854 in.) Crankshaft Bearings Inspect the crankshaft bearings for: •...

  • Page 111: Inspecting The Camshaft And Valves

    Powerhead Measure the plastigauge at its maximum compressed width. 26697 Connecting Rod Oil clearance (standard) 0.015–0.041 mm (0.0006–0.0016 in.) Oil clearance (service limit) 0.060 mm (0.0024 in.) If the oil clearance is out of specification limit, measure the diameter of the connecting rod and the crankpin journal. Replace as needed.

  • Page 112: Lifters And Push Rods

    Powerhead Measure the valve stem outer diameter. Replace the valves if out of specification. 20971 Valve Stem O.D. Intake 5.45–5.47 mm (0.2146–0.2154 in.) Exhaust 5.44–5.46 mm (0.2142–0.2150 in.) Lifters and Push Rods Replace the valve lifter if worn or corroded. Replace the push rod if worn or corroded.

  • Page 113: Valve Guides

    Powerhead NOTE: Check each spring on a flat surface using a square. Rotate spring and check space between the top coil and square. 20974 Valve Spring Tilt limit 2.0 mm (0.0787 in.) Valve Guides Measure the valve guide inner diameter. If valve guide wear is out of specification, replace the cylinder head. Valve guide I.D.
  • Page 114 Powerhead Start with the 45° cutting tool to clean up any pitting or rough surface of the valve seat. 45° Rough surface of valve seat 20954 Use the 30° cutting tool to adjust the contact width of the top edge of the valve seat. Previous contact width 30°...

  • Page 115: Piston/Crankshaft Reassembly

    Powerhead 12. If the valve seat contact area is too narrow and situated near the bottom of the valve face, use the 60° cutting tool to cut the bottom edge of the valve seat. If necessary, use the 45° cutting tool to center the area of contact and set its width. Previous contact width 60°...

  • Page 116: Piston/Crankshaft Installation

    Powerhead Lubricate rings with 4‑Stroke 10W‑30 Outboard Oil after rings are installed on piston. 3150 Top oil control ring Expander Bottom oil control ring Second ring Top ring End gap ‑ Top ring End gap ‑ Bottom oil control ring End gap ‑...

  • Page 117: Powerhead Assembly

    Powerhead Tighten the connecting rod cap screws to the specified torque in two stages. Connecting rod Arrowhead and match mark Connecting rod cap Crankshaft 26687 Tube Ref No. Description Where Used Part No. 4-Stroke 10W-30 Connecting rod, connecting rod cap, and the crankpin 92-858045K01 Outboard Oil journal...
  • Page 118 Powerhead Install the valve lifters and push rods. Intake valve Exhaust valve Valve lifter and push rod 26716 Install the spring seat, spring, and valve spring retainer. Use a suitable box end wrench to compress the valve spring to install the valve keepers. NOTE: Hold the valves in place from the cylinder bore end during the assembly procedure.

  • Page 119: Cylinder Block Assembly

    Powerhead Cylinder Block Assembly IMPORTANT: The cylinder bore must be clean before installing the piston. Clean with light honing oil, as necessary. After honing, clean the cylinder bore with water and detergent. After cleaning, swab the cylinder bore several times with outboard oil and a clean cloth, then wipe with a clean dry cloth.

  • Page 120: Driveshaft Seal Replacement

    Powerhead 14. Apply a continuous bead of Loctite Master Gasket to the contact surface of the crankcase. Follow the instructions contained in the Loctite Master Gasket Kit. Camshaft/gear assembly Crankshaft timing mark Camshaft timing mark Cylinder block mating surface 26599 Tube Ref No.

  • Page 121: Oil Pan Installation

    Powerhead Install new seals and O‑ring. O‑ring Driveshaft seals (2) Driveshaft seal housing 26592 Tube Ref No. Description Where Used Part No. 4-Stroke 10W-30 Driveshaft seal housing O-rings 92-858045K01 Outboard Oil 2-4-C with PTFE Inside diameter of the driveshaft seals 92-802859A 1 Oil Pan Installation Clean the gasket surface of the cylinder block and the oil pan.
  • Page 122 Powerhead Secure the driveshaft seal housing to the oil pan with the two bolts. Tighten the bolts to the specified torque. Driveshaft seal housing bolts (M6 x 20) (8) 26596 Tube Ref No. Description Where Used Part No. Loctite 242 Threadlocker Driveshaft seal housing bolts 92-809821 Description...

  • Page 123: Powerhead Installation

    Powerhead 11. Secure the fuel shutoff valve bracket to the cylinder block with two bolts. Tighten the bolts to the specified torque. Oil sight gauge hose Fuel pump inlet hose Fuel shutoff valve Fuel shutoff valve bracket Bolt (M6 x 20) with washer Fuel tank outlet hose 50014 Description...
  • Page 124 Powerhead Secure the powerhead to the driveshaft housing with seven bolts. Tighten the bolts in sequence to the specified torque. Driveshaft Gasket surface 26703 Tube Ref No. Description Where Used Part No. 2-4-C with PTFE Driveshaft splines 92-802859A 1 Description lb‑in.
  • Page 125 Powerhead 17. Secure the choke cable with the J‑clamp and the washer and bolt. J‑clamp Washer and bolt securing choke cable Fuel hose to the fuel pump Fuel shutoff valve Fuel shutoff valve knob Fuel hose from the fuel pump Bracket 49878 18.
  • Page 126 Clamp/Swivel Bracket and Driveshaft Housing Midsection Section 5A - Clamp/Swivel Bracket and Driveshaft Housing Table of Contents Cowling Components............5A-4 Swivel Bracket Removal/Installation........ 5A-12 Clamp Bracket Components..........5A-6 Removal..............5A-12 Driveshaft Housing Components........5A-8 Steering Co‑Pilot Components......... 5A-13 Clamp Bracket Removal and Installation......5A-10 Steering Stop Components........5A-14 Removal and Disassembly........
  • Page 127 Clamp/Swivel Bracket and Driveshaft Housing Lubricants, Sealants, Adhesives Tube Ref No. Description Where Used Part No. Loctite 271 Threadlocker Swivel bracket special flange head bolts 92-809819 Driveshaft housing between flanges, swivel bracket thrust plate, 2-4-C with PTFE and plastic bushing 92-802859A 1 Swivel bracket rubber bushing Page 5A-2...
  • Page 128 Clamp/Swivel Bracket and Driveshaft Housing Notes: 90-8M0065421 NOVEMBER 2012 Page 5A-3...

  • Page 129: Cowling Components

    Clamp/Swivel Bracket and Driveshaft Housing Cowling Components 22482 Page 5A-4 90-8M0065421 NOVEMBER 2012...
  • Page 130 Clamp/Swivel Bracket and Driveshaft Housing Cowling Components Torque Ref. No. Qty. Description lb‑in. lb‑ft Top cowl Cowl seal Tilt handle Washer Lockwasher Bottom cowl Spark plug decal Cowl latch Collar Bolt Bolt Washer Collar Fuel level decal Oil level decal Shift decal Bushing Auxiliary start rope...

  • Page 131: Clamp Bracket Components

    Clamp/Swivel Bracket and Driveshaft Housing Clamp Bracket Components 22490 Page 5A-6 90-8M0065421 NOVEMBER 2012...
  • Page 132 Clamp/Swivel Bracket and Driveshaft Housing Clamp Bracket Components Torque Ref. No. Qty. Description lb‑in. lb‑ft Clamp bracket Clamp screw assembly Screw Nut (M8) Washer Washer Thrust support Damper Thrust rod Knob Tilt pin O‑ring Swivel bracket cap Stopper Steering stop lever Spring Bolt Washer...

  • Page 133: Driveshaft Housing Components

    Clamp/Swivel Bracket and Driveshaft Housing Driveshaft Housing Components 22488 Page 5A-8 90-8M0065421 NOVEMBER 2012...
  • Page 134 Clamp/Swivel Bracket and Driveshaft Housing Driveshaft Housing Components Torque Ref. No. Qty. Description lb‑in. lb‑ft Driveshaft housing Plug Dowel pin Driveshaft housing gasket Bolt Flush plug Gasket Steering bracket Bolt Hose Grommet Stud Stopper Bolt Grommet Extension housing Bushing Bolt Dowel pin 90-8M0065421 NOVEMBER 2012 Page 5A-9...

  • Page 135: Clamp Bracket Removal And Installation

    Clamp/Swivel Bracket and Driveshaft Housing Clamp Bracket Removal and Installation Removal and Disassembly Remove the locknut on the port clamp bracket. Remove the bolt. Remove the clamp brackets from the swivel bracket. Port clamp bracket Swivel bracket Locknut 26114 Remove the nut and washer from each end of the spacer rod. Remove the tilt pin from the starboard clamp bracket.
  • Page 136 Clamp/Swivel Bracket and Driveshaft Housing Install the thrust support and damper onto the tilt pin. Starboard clamp bracket Spacer rod Tilt pin Thrust support and damper 26121 Assemble the port clamp bracket to the starboard clamp bracket, spacer rod, and tilt pin. Install a washer and nut to the spacer rod.

  • Page 137: Swivel Bracket Removal/Installation

    Clamp/Swivel Bracket and Driveshaft Housing 10. Install the bolt through the clamp brackets (start from the starboard side) and the front swivel bracket. Install a locknut onto the bolt. Tighten the locknut to the specified torque. Port clamp bracket Swivel bracket Locknut 26114 Description...

  • Page 138: Steering Co-Pilot Components

    Clamp/Swivel Bracket and Driveshaft Housing Remove the thrust plate and split plastic bushing. Thrust plate Rubber bushing Split plastic bushing Front swivel bracket 26140 Steering Co‑Pilot Components 26135 Swivel bracket cap Pocket for split plastic bushing tab Friction pad Washer and spring Steering co‑pilot adjusting screw 90-8M0065421 NOVEMBER 2012 Page 5A-13...

  • Page 139: Steering Stop Components

    Clamp/Swivel Bracket and Driveshaft Housing Steering Stop Components Stopper and pin Steering stop lever Bolt and washer Spring ends Swivel bracket 26145 Installation Lubricate the driveshaft housing between the upper and lower flanges with 2‑4‑C with PTFE. Install the thrust plate and split plastic bushing onto the driveshaft housing. NOTE: Install the split plastic bushing with the split facing towards the front of the engine.
  • Page 140 Clamp/Swivel Bracket and Driveshaft Housing Lubricate the inside of the rubber bushing with 2‑4‑C with PTFE. Rubber bushing Swivel bracket 26157 Tube Ref No. Description Where Used Part No. 2-4-C with PTFE Swivel bracket rubber bushing 92-802859A 1 Install the swivel bracket with the rubber bushing onto the driveshaft housing. Thrust plate Rubber bushing Split plastic bushing...
  • Page 141 Clamp/Swivel Bracket and Driveshaft Housing Tube Ref No. Description Where Used Part No. Loctite 271 Threadlocker Swivel bracket special flange head bolts 92-809819 Description lb‑in. lb‑ft Swivel bracket special flange head bolts (4) (M6 x 35) Page 5A-16 90-8M0065421 NOVEMBER 2012...
  • Page 142 Gear Housing Lower Unit Section 6A - Gear Housing Table of Contents Gear Housing Specifications..........6A-2 Lower Driveshaft Bearing/Forward Gear Bearing..6A-20 Gear Housing (Driveshaft)..........6A-4 Gear Housing Assembly..........6A-21 Gear Housing (Propeller Shaft)..........6A-6 Propeller Shaft Assembly......... 6A-21 Shift Linkage Components..........6A-8 Lower Driveshaft Bearing......... 6A-21 General Service Recommendations........

  • Page 143: Gear Housing Specifications

    Gear Housing Gear Housing Specifications Gear Housing Specifications Gear ratio Model 2.5/3.5 2.15:1 Gear housing capacity 180 mL (6.1 fl oz) Gear lubricant type Premium or High Performance Gear Lubricant Pinion teeth Forward gear teeth Clutch Dog type (forward ‑ neutral) Forward gear backlash 0.050–0.152 mm (0.002–0.006 in.) Propeller drive system...
  • Page 144 Gear Housing Dial Indicator 91‑58222A1 Measures distance, movement, and runout; used for drive system assembly and engine setup 9479 Protector Cap 91‑24161 Protects the crankshaft when removing the flywheel; use with flywheel puller (91‑849154T 1) 13445 Universal Puller Plate 91‑37241 Removes bearings from gears and the driveshaft 8505 Puller...

  • Page 145: Gear Housing (Driveshaft)

    Gear Housing Gear Housing (Driveshaft) 42491 Page 6A-4 90-8M0065421 NOVEMBER 2012...
  • Page 146 Gear Housing Gear Housing (Driveshaft) Torque Ref. No. Qty. Description lb‑in. lb‑ft Gear housing Ball bearing Plug Gasket Anode Bolt (M6 x 16) Pinion gear Spacer Driveshaft Ball bearing Water pump base Oil seal Water pump base gasket Roll pin Gasket Water pump guide plate Water pump cover gasket...

  • Page 147: Gear Housing (Propeller Shaft)

    Gear Housing Gear Housing (Propeller Shaft) 22478 Page 6A-6 90-8M0065421 NOVEMBER 2012...
  • Page 148 Gear Housing Gear Housing (Propeller Shaft) Torque Ref. No. Qty. Description lb‑in. lb‑ft Gear housing Ball bearing Shim (0.1) (0.15) Forward gear Cam follower Spring Clutch Propeller shaft Bearing carrier assembly Bearing carrier Ball bearing Oil seal O‑ring Bolt Shear pin (stainless steel) Propeller Cotter pin 90-8M0065421 NOVEMBER 2012...

  • Page 149: Shift Linkage Components

    Gear Housing Shift Linkage Components 22474 Page 6A-8 90-8M0065421 NOVEMBER 2012...
  • Page 150 Gear Housing Shift Linkage Components Torque Ref. No. Qty. Description lb‑in. lb‑ft Shift lever Spring Detent ball Washer O‑ring Shift shaft lever Screw (M5 x 12) Upper shift shaft Washer Cotter pin Joint Bolt (M6 x 16) O‑ring Bushing O‑ring Lower shift shaft Clutch cam 90-8M0065421 NOVEMBER 2012...

  • Page 151: General Service Recommendations

    Gear Housing General Service Recommendations There may be more than one way to disassemble or reassemble a particular part. It is recommended that the entire procedure be read prior to repair. IMPORTANT: Read the following before attempting any repairs. Disassembly of a subassembly may not be necessary until cleaning and inspection reveals that disassembly is required for replacement of one or more components.

  • Page 152: Propeller Removal

    Gear Housing Note the color of the gear lubricant. White or cream color indicates the presence of water in the lubricant. Check the drain pan for water separation from the lubricant. The presence of water in the gear lubricant indicates the need for disassembly and inspection of the oil seals, seal surfaces, O‑rings, and gear housing components.
  • Page 153 Gear Housing WARNING Accidental starting can cause serious injury. Before removing or installing the gear housing, disconnect and isolate the spark plug leads. Disable the ignition system by removing the keys from the ignition (if equipped) and engaging the lanyard stop switch to prevent the engine from starting.

  • Page 154: Gear Housing Disassembly

    Gear Housing Gear Housing Disassembly Water Pump Remove the four bolts securing the water pump housing. Bolts Water pump housing 25535 Use padding to protect the gear housing surface while applying pressure against the housing pry points. Pry points 25536 Remove the impeller and drive key from the driveshaft.
  • Page 155 Gear Housing Inspect the pump cover for damage from excessive heat ‑ charring, blistering, or discoloration. Replace the cover as required. Remove the base plate and the gasket. Base plate Gasket 25539 IMPORTANT: If only water pump repair procedures are to be performed, hold the driveshaft down while prying/lifting up on the pump base to prevent the driveshaft from disconnecting from the pinion gear.

  • Page 156: Bearing Carrier And Propeller Shaft

    Gear Housing Pump base O‑ring 25545 The water pump base seal should be replaced as a normal repair procedure. Use a punch to remove the seal, being careful not to damage the pump base seal surface. If the surface is damaged, replace the water pump base. Apply 2‑4‑C with PTFE to the new seal lips.
  • Page 157 Gear Housing Tap on either side of the carrier with a leather/rubber mallet to break the adhesion between the carrier and the gear housing. Remove the carrier and the propeller shaft. Carrier Propeller shaft 25553 Inspect the carrier ball bearing for serviceability. If the bearing is rusted or does not roll freely, replace the bearing. If the bearing must be replaced, use a slide hammer with the following Snap‑On Tools: •...

  • Page 158: Propeller Shaft Disassembly

    Gear Housing NOTE: The propeller shaft seal cannot be replaced without removing the carrier bearing. Removal of the bearing may damage the bearing. Do not remove the bearing unless necessary and at that time, replace the propeller shaft seal. Remove the seal with a punch being careful not to scar the carrier seal surface. If the surface is damaged, the carrier must be replaced.

  • Page 159: Driveshaft, Pinion Gear, And Forward Gear

    Gear Housing • Propeller shaft has a noticeable wobble or is bent more than 0.152 mm (0.006 in.). Check the propeller shaft trueness with a dial indicator and V‑blocks. V‑blocks Bearing surfaces Check with dial indicator here 25557 Dial Indicator 91‑58222A1 Driveshaft, Pinion Gear, and Forward Gear Remove the driveshaft and spacer from the gear housing.

  • Page 160: Upper Driveshaft Bearing

    Gear Housing Inspect the shift cam face for roughness or galling from the cam follower. If the cam face is worn, replace the shift cam assembly. Cam face 25568 Remove the forward gear and shim. • Inspect the forward gear clutch teeth for wear. •...

  • Page 161: Lower Driveshaft Bearing/Forward Gear Bearing

    Gear Housing Inspect the driveshaft where the water pump seals ride. If a fingernail can catch in the grooves, the driveshaft should be replaced. Seal surface 25611 Lower Driveshaft Bearing/Forward Gear Bearing IMPORTANT: Do not remove the forward gear ball bearing or the lower driveshaft ball bearing from the gear housing unless replacement is necessary.

  • Page 162: Gear Housing Assembly

    Gear Housing Puller 91‑27780 Gear Housing Assembly Propeller Shaft Assembly Compress the clutch spring and insert the clutch into the propeller shaft. Apply a small amount of 2‑4‑C with PTFE to the clutch end of the cam follower. This will aid in retaining the cam follower in the propeller shaft during installation of the propeller shaft into the gear housing.

  • Page 163: Forward Gear

    Gear Housing Lubricate the outside diameter of the bearing with Premium Gear Lubricant. Position the bearing in the gear housing. Seat the bearing in the gear housing using a mandrel and a driver from the bearing removal and installation kit. Bearing Mandrel (38628) Driver (91‑37323)

  • Page 164: Driveshaft

    Gear Housing Driveshaft Lubricate the inside diameter of the new upper driveshaft bearing with Premium Gear Lubricant. In order to position the bearing at the proper height on the driveshaft, fabricate a driver tool to the following dimensions: 92.07 mm (3‑5/8 in.) 19.05 mm (3/4 in.) 10/31 mm (13/32 in.) 25630...

  • Page 165: Bearing Carrier Assembly

    Gear Housing Slide the driveshaft assembly through the spacer into the gear housing while installing the pinion gear onto the lower driveshaft splines. Driveshaft Pinion gear 25633 Bearing Carrier Assembly Apply 2‑4‑C with PTFE to the new seal lips. Press the new seal (flat side down) into the carrier with a 13/16 in. socket. Seal (flat side down) Socket 25638...

  • Page 166: Shift Shaft

    Gear Housing Press the new ball bearing (number side up) into the carrier until the bearing seats. Use a press with a driver and mandrel from the bearing removal and installation kit. Bearing Mandrel (37312) 25639 Tube Ref No. Description Where Used Part No.

  • Page 167: Forward Gear Backlash

    Gear Housing Tube Ref No. Description Where Used Part No. 2-4-C with PTFE Shift shaft surface 92-802859A 1 Forward Gear Backlash Check forward gear backlash as follows: • Apply down pressure on the driveshaft • Push up on the pinion gear (gear floats on the driveshaft) •...

  • Page 168: Water Pump

    Gear Housing Water Pump Install a new base gasket, base plate (if required), and a pump cover gasket. Base gasket Base plate Pump cover gasket 25642 Install the drive key and the impeller onto the driveshaft. If reusing the old impeller, do not reverse the impeller vanes or premature failure will occur.

  • Page 169: Gear Housing

    Gear Housing Secure the water pump cover to the gear housing with four bolts. Tighten the bolts to the specified torque. Lubricate the I.D. of the water tube seal with a light coat of 2‑4‑C with PTFE. Bolts Seal 25645 Tube Ref No.

  • Page 170: Gear Housing Installation

    Gear Housing Using Premium Gear Lubricant, insert the lubricant tube into the oil fill hole and then remove the oil level screw and gasket. Level screw with gasket Fill screw with gasket OIL LEVEL 25501 Tube Ref No. Description Where Used Part No.
  • Page 171 Gear Housing Secure the gear housing to the driveshaft housing with two bolts. Tighten the bolts to the specified torque. Bolts, flat washers, and lockwashers 25534 Tube Ref No. Description Where Used Part No. 2-4-C with PTFE Driveshaft splines 92-802859A 1 Description lb‑in.

  • Page 172: Propeller Installation

    Gear Housing Inspect the sacrificial anode on the bottom of the anti‑ventilation plate for erosion. If it is 50% or more consumed, replace the anode. Do not paint or apply a protective coating to the anode or corrosion protection will be lost. Anode 25649 Description...
  • Page 173 Gear Housing Notes: Page 6A-32 90-8M0065421 NOVEMBER 2012...
  • Page 174 Shift Linkage Attachments Section 7A - Shift Linkage Table of Contents Shift Linkage Components..........7A-4 Shift Linkage Removal..........7A-6 Shift Linkage Removal and Installation......7A-6 Shift Linkage Installation..........7A-7 90-8M0065421 NOVEMBER 2012 Page 7A-1...
  • Page 175 Shift Linkage Lubricants, Sealants, Adhesives Tube Ref No. Description Where Used Part No. 2-4-C with PTFE Shift lever shaft and O-rings 92-802859A 1 Page 7A-2 90-8M0065421 NOVEMBER 2012...
  • Page 176 Shift Linkage Notes: 90-8M0065421 NOVEMBER 2012 Page 7A-3...

  • Page 177: Shift Linkage Components

    Shift Linkage Shift Linkage Components 22474 Page 7A-4 90-8M0065421 NOVEMBER 2012...
  • Page 178 Shift Linkage Shift Linkage Components Torque Ref. No. Qty. Description lb‑in. lb‑ft Shift lever Spring Detent ball Washer O‑ring Shift shaft lever Screw (M5 x 12) Upper shift shaft Washer Cotter pin Joint Bolt (M6 x 16) O‑ring Bushing O‑ring Lower shift shaft Clutch cam 90-8M0065421 NOVEMBER 2012...

  • Page 179: Shift Linkage Removal

    Shift Linkage Shift Linkage Removal and Installation Shift Linkage Removal Remove the powerhead. Refer to Section 4A ‑ Powerhead Removal. Remove the screw retaining the shift lever. Remove the shift lever from the driveshaft housing. Remove the cotter pin from the upper shift shaft. Remove the shift shaft lever from the upper shift shaft.

  • Page 180: Shift Linkage Installation

    Shift Linkage Remove the detent ball and spring from the driveshaft housing. 26790 Shift Linkage Installation Install the spring and detent ball into the driveshaft housing. Lubricate the O‑rings and shaft on the shift lever with 2‑4‑C with PTFE. Install the shift lever into the driveshaft housing. Install a washer onto the shift lever.
  • Page 181 Shift Linkage Install the powerhead. Refer to Section 4A ‑ Powerhead Installation. Page 7A-8 90-8M0065421 NOVEMBER 2012...
  • Page 182 Tiller Handle Attachments Section 7B - Tiller Handle Table of Contents Tiller Handle Components..........7B-4 Tiller Handle Installation.............7B-9 Tiller Handle Removal............7B-6 Throttle Cable Adjustment..........7B-11 Tiller Handle Disassembly..........7B-7 Deceleration Cable........... 7B-11 Tiller Handle Reassembly..........7B-7 Acceleration Cable............7B-12 90-8M0065421 NOVEMBER 2012 Page 7B-1...
  • Page 183 Tiller Handle Lubricants, Sealants, Adhesives Tube Ref No. Description Where Used Part No. Loctite 242 Threadlocker Fuel tank mounting bolts 92-809821 Page 7B-2 90-8M0065421 NOVEMBER 2012...
  • Page 184 Tiller Handle Notes: 90-8M0065421 NOVEMBER 2012 Page 7B-3...

  • Page 185: Tiller Handle Components

    Tiller Handle Tiller Handle Components 22485 Page 7B-4 90-8M0065421 NOVEMBER 2012...
  • Page 186 Tiller Handle Tiller Handle Components Torque Ref. No. Qty. Description lb‑in. lb‑ft Tiller handle Grip Rubber shaft Bushing Screw Drive tight Bracket Screw Drive tight Throttle shaft friction device Throttle friction knob As required Spring Bolt Throttle shaft Throttle decal Rubber isolator bushing Cover Bolt...

  • Page 187: Tiller Handle Removal

    Tiller Handle Tiller Handle Removal WARNING Fuel is flammable and explosive. Ensure that the key switch is off and the lanyard is positioned so that the engine cannot start. Do not smoke or allow sources of spark or open flame in the area while servicing. Keep the work area well ventilated and avoid prolonged exposure to vapors.

  • Page 188: Tiller Handle Disassembly

    Tiller Handle Tiller Handle Disassembly Remove the screw from the tiller handle grip. Slide the grip off of the tiller handle. Loosen the friction knob. Remove the screw from the tiller handle bracket. Remove the throttle shaft from the tiller handle. Place a match mark on the acceleration throttle cable and cable end.
  • Page 189 Tiller Handle Install the bushing and rubber shaft onto the throttle shaft. 26033 Rubber shaft Bushing Throttle shaft Throttle friction components Tiller handle Install the throttle cables through the slot in the tiller handle cover. Tiller handle cover slot Throttle cable ‑ deceleration Throttle cable ‑...

  • Page 190: Tiller Handle Installation

    Tiller Handle Adjust the friction knob to the desired setting. 26044 Tiller handle grip screw Grip Friction knob Throttle shaft bracket screw Throttle shaft bracket Tiller Handle Installation Install the tiller handle and steering bracket into the opening in the bottom cowl. Secure the tiller handle to the bottom cowl with two bolts and washers.
  • Page 191 Tiller Handle Install the throttle cables into the slots on the throttle cable bracket. Throttle cable A Throttle cable B Throttle drum Throttle cable end of cable B Throttle cable end of cable A Throttle drum bolt Throttle cable bracket slots 26047 Description lb‑in.

  • Page 192: Throttle Cable Adjustment

    Tiller Handle Apply Loctite 242 Threadlocker to the fuel tank mounting bolts. Install the bolts and washers. Tighten the bolts to the specified torque. Fuel tank Bolt and washer (M6 x 25) (3) 50010 Tube Ref No. Description Where Used Part No.

  • Page 193: Acceleration Cable

    Tiller Handle Ensure the gap between the tab on the throttle drum and the edge of the notch on the throttle opener is within specification. 41821 Deceleration cable adjustment Throttle opener Throttle drum Gap measurement Gap measurement Throttle drum/throttle opener 0.5–1.0 mm (0.020–0.040 in.) Acceleration Cable Rotate the grip to the WOT position.
  • Page 194 Recoil Starter Manual Starter Section 8A - Recoil Starter Table of Contents Recoil Starter Components..........8A-4 Recoil Starter Rope Replacement........8A-9 Recoil Starter Removal............8A-6 Removal..............8A-9 Recoil Starter Spring Replacement........8A-7 Reassembly.............. 8A-10 Removal..............8A-7 Recoil Starter Installation..........8A-11 Reassembly..............8A-8 90-8M0065421 NOVEMBER 2012 Page 8A-1...
  • Page 195 Recoil Starter Lubricants, Sealants, Adhesives Tube Ref No. Description Where Used Part No. Recoil starter assembly mounting bolts Loctite 242 Threadlocker 92-809821 Fuel tank mounting bolts Page 8A-2 90-8M0065421 NOVEMBER 2012...
  • Page 196 Recoil Starter Notes: 90-8M0065421 NOVEMBER 2012 Page 8A-3...

  • Page 197: Recoil Starter Components

    Recoil Starter Recoil Starter Components 22484 Page 8A-4 90-8M0065421 NOVEMBER 2012...
  • Page 198 Recoil Starter Recoil Starter Components Torque Ref. No. Qty. Description lb‑in. lb‑ft Recoil starter assembly Spring Reel Ratchet pawl Friction plate Screw Drive tight Friction spring Rope Starter handle Rope anchor Rope anchor plate Starter seal Bolt (M6 x 60) Washer Clamp 90-8M0065421 NOVEMBER 2012...

  • Page 199: Recoil Starter Removal

    Recoil Starter Recoil Starter Removal WARNING Fuel is flammable and explosive. Ensure that the key switch is off and the lanyard is positioned so that the engine cannot start. Do not smoke or allow sources of spark or open flame in the area while servicing. Keep the work area well ventilated and avoid prolonged exposure to vapors.

  • Page 200: Recoil Starter Spring Replacement

    Recoil Starter Recoil Starter Spring Replacement WARNING Uncontrolled release of the rewind spring can cause serious injury. Wear eye protection when servicing the rewind starter in case spring should uncoil. Removal Pull the starter rope until it is fully unwound from the reel. Hold the reel in this position. Untie or cut the knot from the rope.

  • Page 201: Reassembly

    Recoil Starter Remove the ratchet pawls from the reel. Ratchet pawl (2) Reel 25965 Carefully remove the reel (with spring) from the recoil starter housing. NOTE: The spring may unwind as the reel is removed from the housing. Remove the spring from the reel spring cavity. Reassembly Install the hook on the end of the spring into the reel.

  • Page 202: Recoil Starter Rope Replacement

    Recoil Starter Install the ratchet pawls into the holes marked "R". Install the friction plate and screw into the reel and housing. Drive the screw tight. Rotate the reel counterclockwise four to five turns and hold the reel in this position. Route the rope through the recoil starter housing and through the small hole in the reel.

  • Page 203: Reassembly

    Recoil Starter Untie or cut the knot from the rope. Friction plate Screw Reel Knot in rope 25957 Slowly allow the reel to unwind to release spring tension. Remove the rope anchor from the handle. Remove the starter rope from the handle. Reassembly Tie a knot onto one end of the starter rope.

  • Page 204: Recoil Starter Installation

    Recoil Starter Continue to hold the reel and slowly let the reel unwind, pulling the rope and handle into the housing. Recoil Starter Installation Ensure the flywheel cover is in place. Flywheel Flywheel cover 41824 Secure the fuel hose and choke cable with the J‑clamp. Apply Loctite 242 Threadlocker to the recoil starter assembly mounting bolts.
  • Page 205 Recoil Starter WARNING Fuel is flammable and explosive. Ensure that the key switch is off and the lanyard is positioned so that the engine cannot start. Do not smoke or allow sources of spark or open flame in the area while servicing. Keep the work area well ventilated and avoid prolonged exposure to vapors.

This manual is also suitable for:

Fourstroke 3.5Fourstroke f3.5 mlh

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