Mercury 250 XS OptiMax Operation, Maintenance & Installation Manual
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Mercury 250 XS OptiMax Operation, Maintenance & Installation Manual

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Summary of Contents for Mercury 250 XS OptiMax

  • Page 1 Operation Maintenance Installation Manual...
  • Page 3 Thank you for purchasing one of our products. We sincerely hope your boating will be pleasant! Mercury Marine, Fond du Lac, Wisconsin, U.S.A. Name / function: John Pfeifer, President, Mercury Marine...
  • Page 4 Warranty Message The product you have purchased comes with a limited warranty from Mercury Marine; the terms of the warranty are set forth in the Warranty Manual included with the product. The Warranty Manual contains a description of what is...
  • Page 5 Identification Records Please record the following applicable information: Outboard Engine Model and Horsepower Engine Serial Number Gear Ratio Propeller Number Pitch Diameter Hull Identification Number (HIN) Purchase Date Boat Manufacturer Boat Model Length Exhaust Gas Emissions Certification Number (Europe Only)

  • Page 7: Table Of Contents

    Low Permeation Fuel Hose Requirement ............23 EPA Pressurized Portable Fuel Tank Requirements........23 Fuel Demand Valve (FDV) Requirement............23 Mercury Marine's Pressurized Portable Fuel Tank........... 24 Filling Remote Oil Tank..................25 Filling Engine Mounted Oil Reservoir Tank............25 Filling Fuel Tank....................26...
  • Page 8 Features and Controls Remote Control Features................. 27 Zero Effort Control Features................28 Warning System....................28 Power Trim and Tilt................... 30 Power Trim Operation ..................30 Power Tilt Operation (Single‑Ram Systems)............ 32 Power Tilt Operation (Three‑Ram Trim Systems)..........32 Auxiliary Tilt Switch................... 33 Manual Tilt Operation..................
  • Page 9 Maintenance Cleaning Care Recommendations..............45 Power Package Care..................47 Replacement Parts for Your Power Package........... 47 EPA Emissions Regulations................47 Inspection and Maintenance Schedule............. 48 Flushing the Cooling System (Powerhead)............50 Flushing the Cooling System (Lower Unit)............51 Top Cowl Removal and Installation..............52 Fuel System......................
  • Page 10 Owner Service Assistance Service Assistance................... 78 Ordering Literature.................... 80 Outboard Installation Mercury Marine Validated Engine Mounting Hardware........82 Accessories Mounted to the Transom Clamp Bracket........82 Boat Horsepower Capacity................86 Start in Gear Protection..................86 Fuel System...................... 87 Installation Specifications................. 89 Lifting the Outboard..................

  • Page 11: General Information

    GENERAL INFORMATION Boater's Responsibilities The operator (driver) is responsible for the correct and safe operation of the boat and the safety of its occupants and general public. It is strongly recommended that each operator read and understand this entire manual before operating the outboard.

  • Page 12: High-Speed And High-Performance Boat Operation

    For additional information, obtain a copy of our Hi‑Performance Boat Operation booklet from your dealer, distributor, or Mercury Marine. Outboard Remote Control Models The remote control connected to your outboard must be equipped with a start in neutral only protection device.

  • Page 13: Remote Steering Notice

    GENERAL INFORMATION Remote Steering Notice The steering link rod that connects the steering cable to the engine must be fastened utilizing self‑locking nuts. These self‑locking nuts must never be replaced with common nuts (nonlocking) as they will work loose and vibrate off, freeing the link rod to disengage.
  • Page 14 GENERAL INFORMATION The lanyard cord is usually 122–152 cm (4–5 feet) in length when stretched out, with an element on one end made to be inserted into the switch and a clip on the other end for attaching to the operator's PFD or wrist. The lanyard is coiled to make its at‑rest condition as short as possible to minimize the likelihood of lanyard entanglement with nearby objects.
  • Page 15 GENERAL INFORMATION While activation of the lanyard stop switch will stop the engine immediately, a boat will continue to coast for some distance depending upon the velocity and degree of any turn at shut down. However, the boat will not complete a full circle.

  • Page 16: Protecting People In The Water

    GENERAL INFORMATION Protecting People in the Water WHILE YOU ARE CRUISING It is very difficult for a person in the water to take quick action to avoid a boat heading in their direction, even at slow speeds. 21604 Always slow down and exercise extreme caution any time you are boating in an area where there might be people in the water.
  • Page 17 GENERAL INFORMATION Persons on the front deck could easily be thrown overboard or persons dangling their feet over the front edge could get their legs caught by a wave and pulled into the water. 26782 WARNING Sitting or standing in an area of the boat not designed for passengers at speeds above idle can cause serious injury or death.

  • Page 18: Wave And Wake Jumping

    GENERAL INFORMATION Wave and Wake Jumping Operating recreational boats over waves and wake is a natural part of boating. However, when this activity is done with sufficient speed to force the boat hull partially or completely out of the water, certain hazards arise, particularly when the boat enters the water.

  • Page 19: Impact With Underwater Hazards

    GENERAL INFORMATION Impact with Underwater Hazards Reduce speed and proceed with caution whenever you drive a boat in shallow water areas, or in areas where you suspect underwater obstacles may exist which could be struck by the outboard or the boat bottom. The most important thing you can do to help reduce injury or impact damage from striking a floating or underwater object is to control the boat speed.

  • Page 20: Exhaust Emissions

    Operating a boat or engine with impact damage can result in product damage, serious injury, or death. If the vessel experiences any form of impact, have an authorized Mercury Marine dealer inspect and repair the vessel or power package. Exhaust Emissions...
  • Page 21 GENERAL INFORMATION GOOD VENTILATION Ventilate the passenger area, open side curtains or forward hatches to remove fumes. Example of desired air flow through the boat: 21622 POOR VENTILATION Under certain running and/or wind conditions, permanently enclosed or canvas enclosed cabins or cockpits with insufficient ventilation may draw in carbon monoxide.

  • Page 22: Selecting Accessories For Your Outboard

    Some accessories not manufactured or sold by Mercury Marine are not designed to be safely used with your outboard or outboard operating system. Read the installation, operation and maintenance manuals for all your selected accessories.
  • Page 23 (refer to your boat's capacity plate). Know your boat's operating and loading limitations. Know if your boat will float if it is full of water. When in doubt, contact your authorized Mercury Marine dealer or the boat manufacturer. Ensure that everyone in the boat is properly seated.

  • Page 24: Recording Serial Number

    GENERAL INFORMATION Be alert. • The operator of the boat is responsible by law to maintain a proper lookout by sight and hearing. The operator must have an unobstructed view particularly to the front. No passengers, load, or fishing seats should block the operator's view when the boat is above idle or planing transition speed.

  • Page 25: Specifications-250 Xs Optimax

    GENERAL INFORMATION Specifications—250 XS OptiMax Attribute Specifications Horsepower 250 HP (184 kw) Engine displacement 3038 cc (185 cid) 20 in. 229 kg (505 lb) Sport Master Engine 25 in. 237 kg (522 lb) weight Fleet Master 30 in. 242 kg (533 lb)

  • Page 26: Specifications-300Xs Optimax

    *Battery manufacturers may rate and test their batteries to different standards. MCA, CCA, Ah, and reserve capacity (RC) are the ratings recognized by Mercury Marine. Manufacturers that use standards different than these, such as equivalent MCA, do not meet Mercury Marine battery requirements.
  • Page 27 GENERAL INFORMATION Specifications 20 in. 6350 RPM (Torque Master) 20 in. 6350 RPM (Sport Master) 25 in. Overspeed rev limit 6350 RPM (Torque Master) 25 in. 5900 RPM (Fleet Master) 30 in. Models 5900 RPM (Fleet Master) Idle RPM 585 RPM Neutral rev limit 1900 RPM Cylinder configuration...

  • Page 28: Special Tools And Kits

    GENERAL INFORMATION Specifications Emission control system Electronic engine control (EC) Special Tools and Kits Description Part Number Stainless Steel Tilt Pin (Three‑Ram Trim Systems) 17‑49930A1 Oil Syringe 91‑803976T Flushing Attachment (for Torque/Fleet Master gearcase) 44357T2 Flushing Attachment (for Sport Master gearcase) 848998A1 Dual Water Pick‑Up Flush Seal Kit (Fleet/Torque Master 881150K1...

  • Page 29: Propeller Selection

    Conversely, propping the engine at the lower end of the range may increase top boat speed but hinder acceleration. Mercury Marine recommends selecting a propeller that allows the engine to operate in the upper half of the recommended full throttle RPM range with the boat normally loaded (refer to General Information ‑...

  • Page 30: Transporting

    TRANSPORTING Trailering Boat/Outboard Trailer your boat with the outboard tilted down in a vertical operating position. If additional ground clearance is required, the outboard should be tilted up using an accessory outboard support device. Refer to your local dealer for recommendations.

  • Page 31: Fuel And Oil

    USA is alcohol (ethanol, methanol, or butanol). GASOLINE CONTAINING ALCOHOL Bu16 Butanol Fuel Blends Fuel blends of up to 16.1% butanol (Bu16) that meet the published Mercury Marine fuel rating requirements are an acceptable substitute for unleaded gasoline. Contact your boat manufacturer for specific recommendations on your boat's fuel system components (fuel tanks, fuel lines, and fittings).

  • Page 32: Oil Recommendation

    Fuel Additives To minimize carbon deposit buildup in the engine, it is recommended to add Mercury or Quicksilver Quickstor fuel stabilizer additive to the engine's fuel at each tank fill throughout the boating season. Use additive as directed on container.

  • Page 33: Avoiding Fuel Flow Restrictions

    FUEL AND OIL Avoiding Fuel Flow Restrictions NOTICE Adding components to the fuel supply system can damage the engine. These additions can restrict fuel flow, stall the engine at low speeds, and create lean fuel conditions at high speeds. Follow all regulations for fuel system installation and do not add any additional components to the fuel system.

  • Page 34: Mercury Marine's Pressurized Portable Fuel Tank

    FUEL AND OIL Mercury Marine's Pressurized Portable Fuel Tank Mercury Marine has created a new portable pressurized fuel tank that meets the preceding EPA requirements. These fuel tanks are available as an accessory or are provided with certain portable outboard models.

  • Page 35: Filling Remote Oil Tank

    FUEL AND OIL DIRECTIONS FOR USING THE PRESSURIZED PORTABLE FUEL TANK 1. When installing the fuel tank cap, turn the cap to the right until you hear a click. This signals that the fuel cap is fully seated. A built‑in device prevents overtightening.

  • Page 36: Filling Fuel Tank

    FUEL AND OIL Filling Fuel Tank WARNING Avoid serious injury or death from a gasoline fire or explosion. Use caution when filling fuel tanks. Always stop the engine and do not smoke or allow open flames or sparks in the area while filling fuel tanks. Fill the fuel tanks outdoors away from heat, sparks, and open flames.

  • Page 37: Features And Controls

    FEATURES AND CONTROLS Remote Control Features Your boat may be equipped with one of the Mercury Precision or Quicksilver remote controls shown. If not, consult your dealer for a description of the functions and operations of the remote control. 26800 Control handle –...

  • Page 38: Zero Effort Control Features

    FEATURES AND CONTROLS Zero Effort Control Features Throttle lever Trim switch Shift lever 4090 Warning System WARNING HORN SIGNALS When the key switch is turned to the ON position, the horn will turn on for a moment as a test to indicate the horn is working. There are two types of warning horns to alert the operator of an active problem within the engine’s operating system.
  • Page 39 2. Engage the throttle. If the engine does not respond, repeat step one. SMARTCRAFT PRODUCT A Mercury SmartCraft System instrument package can be purchased for this outboard. A few of the functions the instrument package will display are engine RPM, coolant temperature, oil pressure, water pressure, battery voltage, fuel consumption, and engine operating hours.

  • Page 40: Power Trim And Tilt

    FEATURES AND CONTROLS Power Trim and Tilt NOTE: Outboard position can be adjusted by pressing trim switch. This range is used while operating your boat on plane. 2726 Trim switch Trim range Tilt range • Pressing (DN): Moves the outboard in closer to the boat transom, called trimming in or down.
  • Page 41 FEATURES AND CONTROLS WARNING Trimming the outboard beyond a neutral steering condition may result in a pull on the steering wheel or tiller handle and loss of boat control. Maintain control of the boat if trimming beyond a neutral steering condition. Consider the following lists carefully.

  • Page 42: Power Tilt Operation (Single-Ram Systems)

    FEATURES AND CONTROLS To limit trim in on models with a single‑ram trim system, use the cadmium plated bolt shipped with the engine. 15923 Stainless steel tilt pin (Three‑Ram trim system) Bolt shipped with engine (Single‑Ram trim system) Trimming out or up can: •...

  • Page 43: Auxiliary Tilt Switch

    FEATURES AND CONTROLS 1. Engage the tilt support lever by pushing the metal stop and rotating the knob to bring the support lever upward. 37214 Tilt support lever Metal stop Knob 2. Lower the outboard to rest on the tilt support lever. 3.
  • Page 44 FEATURES AND CONTROLS 1. Turn out the manual tilt release valve three turns (counterclockwise). This allows manual tilting of the outboard. 2728 2. Tilt the outboard to the desired position and tighten the manual tilt release valve. NOTE: The manual tilt release valve must be tightened before operating the outboard to prevent the outboard from tilting up during reverse operation.

  • Page 45: Operation

    OPERATION Important Information IMPORTANT DAILY INSPECTION BEFORE EACH USE Any outboard mounted on the boat must have the mounting hardware inspected and checked to ensure that the hardware has not become loose. A decal on the transom bracket reminds the owner to check the fasteners securing the outboard to the transom before each use.

  • Page 46: Engine Break-In Fuel Mixture

    OPERATION IMPORTANT: Failure to follow the engine break‑in procedures can result in poor performance throughout the life of the engine and can cause engine damage. Always follow break‑in procedures. Break‑in Procedure Always vary throttle settings during Break‑in 1st Hour • Allow engine to warm‑up for 30–60 seconds.

  • Page 47: Operating In Saltwater Or Polluted Water

    Wash the outboard exterior and flush out the exhaust outlet of the propeller and gearcase with fresh water after each use. Each month, spray Mercury Precision or Quicksilver Corrosion Guard on external metal surfaces. Do not spray on corrosion control anodes as this will reduce the effectiveness of the anodes.

  • Page 48: Setting Trim Angle While Running Engine At Idle Speed

    OPERATION Some boat performance can be improved by dropping to a lower pitch propeller, but engine performance will still remain lower. In some cases, a gear ratio reduction may be more beneficial. To optimize engine performance, prop the engine to allow it to operate at or near the top end of the recommended maximum RPM range at wide‑open throttle with a normal boat load.

  • Page 49: Oil Injection System

    OPERATION Oil Injection System FILLING THE OIL TANKS 1. Remove the fill cap from the remote oil tank and fill the tank with the recommended oil. Install the fill cap and tighten securely. Fill cap 2683 IMPORTANT: Do not remove the vent cap from the engine‑mounted oil reservoir tank when filling the tank.
  • Page 50 OPERATION PRIMING THE OIL INJECTION PUMP Before starting the engine for the first time, prime the oil injection pump. Priming will remove any air that may be in the pump, oil supply hose, or internal passages. 7747 Oil injection pump Oil supply hose IMPORTANT: Fill the engine fuel system with fuel before priming the oil injection pump.

  • Page 51: Starting The Engine

    OPERATION 3. Turn the ignition key switch to the "ON" position. 26846 4. Within the first 10 seconds after the key switch has been turned on, move the remote control handle from neutral into forward gear 3 to 5 times. This will automatically start the priming process.
  • Page 52 OPERATION STARTING PROCEDURE 1. Lower the outboard to the RUN position. Make sure all the cooling water intake holes are submerged. 26837 2. Open fuel tank filler cap vent screw (manual venting fuel tanks). 19748 3. Squeeze the fuel line primer bulb several times until it feels firm. 19779 4.
  • Page 53 OPERATION 5. Shift the outboard to the neutral position. 26838 6. Do not advance the neutral fast idle speed feature on the remote control for starting (if equipped). 27242 7. Turn the ignition key to the START position. Release the key when the engine starts.

  • Page 54: Gear Shifting

    No obstruction may indicate a water pump failure or blockage in the cooling system, which can overheat the engine. Have an authorized Mercury Marine dealer check the system. Gear Shifting IMPORTANT: Observe the following: •...

  • Page 55: Cleaning Care Recommendations

    Record maintenance performed in the Maintenance Log at the back of this book. Save all maintenance work orders and receipts. Selecting Replacement Parts For Your Outboard We recommend using original Mercury Precision or Quicksilver replacement parts and Genuine Lubricants. DO NOT USE CAUSTIC CLEANING CHEMICALS IMPORTANT: Do not use caustic cleaning chemicals on the outboard power package.
  • Page 56 Keep water spray out of the air filter/intake and alternator. After washing, allow the powerhead and components to dry. Apply Quicksilver or Mercury Precision Lubricants Corrosion Guard spray on the external metal surfaces of the powerhead and powerhead components. Do not allow the Corrosion Guard spray to come in contact with the alternator drive belt or belt pulleys.

  • Page 57: Power Package Care

    Mercury recommends using original Mercury Precision replacement parts and lubricants. EPA Emissions Regulations All new 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 set to factory standards.

  • Page 58: Inspection And Maintenance Schedule

    MAINTENANCE EMISSION CERTIFICATION LABEL An emission certification label, showing emission levels and engine specifications directly related to emissions, is placed on the engine at the time of manufacture. EMISSION CONTROL INFORMATION THIS ENGINE CONFORMS TO CALIFORNIA AND U.S. EPA EMISSION REGULATIONS FOR SPARK IGNITION MARINE ENGINES REFER TO OWNERS MANUAL FOR REQUIRED MAINTENANCE, SPECIFICATIONS, AND ADJUSTMENTS IDLE SPEED (in gear):...
  • Page 59 MAINTENANCE • Check the hydraulic steering fluid level, if equipped AFTER EACH USE • Wash the power package exterior with fresh water • Flush the outboard cooling system, saltwater or brackish water only ANNUALLY OR 100 HOURS • Grease the engine, if applicable •...

  • Page 60: Flushing The Cooling System (Powerhead)

    MAINTENANCE Flushing the Cooling System (Powerhead) Flush the internal water passages of the engine 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. 2730 Plug located on fitting Water hose...

  • Page 61: Flushing The Cooling System (Lower Unit)

    MAINTENANCE Flushing the Cooling System (Lower Unit) WARNING Rotating propellers can cause serious injury or death. Never operate the boat out of the water with a propeller installed. Before installing or removing a propeller, place the drive unit in neutral and engage the lanyard stop switch to prevent the engine from starting.

  • Page 62: Top Cowl Removal And Installation

    MAINTENANCE Top Cowl Removal and Installation REMOVAL Release the front and side cowl latches. Lift the top cowl from the outboard. 2732 INSTALLATION Position the top cowl over the engine. Make sure the bottom rubber seal fits properly and lock the front and side latches. Fuel System FUEL SYSTEM SERVICE INFORMATION WARNING...
  • Page 63 MAINTENANCE WATER SEPARATING FUEL FILTER This filter removes moisture and debris from the fuel. If the filter becomes filled with water, the water can be removed. If the filter becomes plugged with debris, replace the filter. The warning system engages when water in the fuel filter reaches the full level.
  • Page 64 IMPORTANT: Visually inspect for fuel leakage from the drain screw by squeezing the primer bulb until firm, forcing fuel into the chamber. If you experience multiple issues with water in the fuel system over a short period of time, see your authorized Mercury dealer.

  • Page 65: Steering Link Rod Fasteners

    MAINTENANCE Steering Link Rod Fasteners IMPORTANT: The steering link rod that connects the steering cable to the engine must be fastened using a special washer head bolt (P/N 10‑849838) and self‑locking nylon insert locknuts (P/N 11‑826709113). Never replace locknuts with common nuts (nonlocking) as they will work loose and vibrate off, freeing the link rod to disengage.

  • Page 66: Fuses

    MAINTENANCE Description lb‑in. lb‑ft Cable coupler nylon insert locknut Tighten locknut until it seats, then "d" loosen ¼ turn. Head bolt nylon insert locknut "b" – Special washer head bolt – Fuses IMPORTANT: Always carry spare 2‑, 15‑, and 20‑amp fuses. The electrical wiring circuits on the engine are protected from overload by fuses in the wiring.

  • Page 67: Corrosion Control Anodes

    Anodes made of insufficiently pure aluminum alloys may not adequately protect critical drive components from corrosion. We recommend using anodes sold through Mercury Precision Parts only. Anodes help protect the power package against galvanic corrosion by sacrificing their metal to be slowly eroded instead of other metals.

  • Page 68: Spark Plug Inspection And Replacement

    MAINTENANCE This model has three corrosion control anodes on the gearcase—two above and one below the anti‑ventilation plate. A fourth anode is located on the bottom of the clamp/swivel bracket assembly. Corrosion control anodes (three on gearcase) Corrosion control anode (one on clamp/swivel bracket) All anodes require periodic inspection, especially in saltwater (refer to the...
  • Page 69 MAINTENANCE IMPORTANT: The color of the plug may not accurately reflect its condition. To accurately diagnose a faulty plug, inspect the precious metal on the plug's electrode. If no precious metal is visible, replace the plug. 9381 Precious metal 3. Set the spark plug gap. Refer to Specifications. 27848 a.

  • Page 70: Battery Inspection

    With the fusible link open, the engine can be started; however, the run time is limited, because the alternator is not charging the boat battery. If the fusible link circuit becomes open, contact your authorized Mercury Marine dealer. 3797...

  • Page 71: Replacing The Propeller

    Choose a propeller that allows the engine to operate at the specified wide open throttle RPM. Mercury Racing applications use 19‑spline propeller shafts and require installation of the Heavy‑Duty Propeller Hub kit, included with most Mercury Racing propellers.
  • Page 72 MAINTENANCE IMPORTANT: To prevent the propeller hub from corroding and seizing to the propeller shaft, especially in salt water, always apply a coat of Extreme Grease to the entire propeller shaft at the recommended maintenance intervals and also each time the propeller is removed. 1.

  • Page 73: Lubrication Points

    MAINTENANCE Lubrication Points Lubricate the following with Extreme Grease and 2‑4‑C with PTFE. 5517 Tube Ref Description Where Used Part No. Extreme Grease Trim rod ball ends, propeller shaft 8M0071842 2-4-C with PTFE Swivel bracket, tilt support lever, tilt tube 92-802859A 1 NOTE: Turn the ball ends to work the lubricant into the ball sockets.

  • Page 74: Single-Ram Trim System

    MAINTENANCE WARNING Incorrect cable lubrication can cause hydraulic lock, leading to serious injury or death from loss of boat control. Completely retract the end of the steering cable before applying lubricant. Lubricate the steering link with lightweight oil. Lubricate the belt tensioner pulley and steering cable with 2‑4‑C with PTFE. 4833 Tube Ref Description...
  • Page 75 MAINTENANCE Optional Accessories Assembly Part Number Floor Mount Kit 842109A01 Bracket Assembly 87762A2 POWER TRIM OPERATION (SINGLE-RAM SYSTEM) The trim system has no trim out limits. Exercise care that engine is not trimmed out beyond safe operation limits. WARNING Trimming the outboard beyond a neutral steering condition may result in a pull on the steering wheel or tiller handle and loss of boat control.
  • Page 76 MAINTENANCE CHECKING POWER TRIM FLUID (SINGLE-RAM TRIM SYSTEMS) 1. Place outboard in the full down/in position. or52 2. Check the fluid level in the trim pump reservoir. The level should be between the "MIN" and "MAX" level marks on the reservoir. 3.

  • Page 77: Three-Ram Trim System

    MAINTENANCE 5. Replace the fill cap. Three‑Ram Trim System GENERAL INFORMATION The power trim system was filled prior to shipment and is ready for use. The outboard can be raised or lowered manually by loosening the manual release valve four turns. Manual release valve 2687 The trim out angle of this outboard is not adjustable.
  • Page 78 MAINTENANCE With most boats, operating around the middle of the trim range will give satisfactory results. However, to take full advantage of the trimming capability, there may be times when you choose to trim your outboard all the way in or out.
  • Page 79 MAINTENANCE CHECKING POWER TRIM FLUID (THREE-RAM TRIM SYSTEMS) 1. Tilt outboard to the full up position and engage the tilt support lock. or47-1 Tilt support lock Tube Ref. No. Description Where Used Part Number Power Trim and Steering Fill hole 92‑802880A1 Fluid 2.

  • Page 80: Gearcase Lubricant

    Fill/drain hole Fill/drain plug Tube Ref Description Where Used Part No. SAE 85W90 Mercury Gearcase 8M0078015 Racing Gear Oil 1. Place the outboard in a vertical operating position. 2. Remove the vent plug (upper plug) and sealing washer. 3. Remove the fill/drain plug (lower plug).

  • Page 81: Submerged Power Package

    MAINTENANCE Water in gear lubricant may: • Settle to bottom and drain out with the lubricant • Be mixed with lubricant giving a milky color to the lubricant Water in gear lubricant will: • Result in premature bearing failure • In freezing temperatures, turn to ice and damage gearcase DRAINING THE GEARCASE or50-1...

  • Page 82: Storage

    IMPORTANT: Fuel containing alcohol (ethanol or methanol) can cause a formation of acid during storage that can damage the fuel system. If the fuel being used contains alcohol, Mercury Marine recommends draining as much of the remaining fuel as possible from the fuel tank, remote fuel line, and engine fuel system.

  • Page 83: Protecting Internal Engine Components

    7. Tighten drain screw and reattach the hose. 8. Premix the following in a container: • 8 cc (0.3 oz.) or 2 teaspoons of Mercury Precision Quickleen lubricant. • 8 cc (0.3 oz.) or 2 teaspoons of Mercury Precision Fuel Stabilizer.

  • Page 84: 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 Description Where Used Part No.

  • Page 85: Troubleshooting

    TROUBLESHOOTING Starter Motor Will Not Crank the Engine POSSIBLE CAUSES • Blown 20‑amp fuse in the starting circuit. Refer to Maintenance. • Outboard is not shifted to neutral position. • Weak battery or battery connections are loose or corroded. • Ignition key switch failure.

  • Page 86: Performance Loss

    TROUBLESHOOTING d. Fuel line is kinked or pinched. e. Injector plugged. • Threaded connection of an air hose is loose. • Fuel pump failure. • Ignition system component failure. Performance Loss POSSIBLE CAUSES • Throttle not fully open. • Damaged propeller or improper propeller size. •...

  • Page 87: Battery Will Not Hold Charge

    TROUBLESHOOTING Battery Will Not Hold Charge POSSIBLE CAUSES • Battery connections are loose or corroded. • Low electrolyte level in battery. • Worn out or inefficient battery. • Excessive use of electrical accessories. • Defective rectifier, alternator, or voltage regulator. •...

  • Page 88: Owner Service Assistance

    STOLEN POWER PACKAGE If your power package is stolen, immediately advise the local authorities and Mercury Marine of the model and serial numbers and to whom the recovery is to be reported. This information is maintained in a database at Mercury Marine to aid authorities and dealers in the recovery of stolen power packages.
  • Page 89 OWNER SERVICE ASSISTANCE RESOLVING A PROBLEM Satisfaction with your Mercury product is important to your dealer and to us. If you ever have a problem, question or concern about your power package, contact your dealer or any authorized Mercury dealership. If you need additional assistance: 1.

  • Page 90: Ordering Literature

    Before ordering literature, have the following information about your power package available: Model Serial Number Horsepower Year UNITED STATES AND CANADA For additional literature for your Mercury Marine power package, contact your nearest Mercury Marine dealer or contact: Mercury Marine Telephone Mail Mercury Marine (920) 929‑5110 (920) 929‑4894...
  • Page 91 OWNER SERVICE ASSISTANCE Mercury Marine Submit the following Attn: Publications Department order form with payment W6250 Pioneer Road P.O. Box 1939 Fond du Lac, WI 54936-1939 Ship To: (Copy this form and print or type–This is your shipping label) Name...

  • Page 92: Outboard Installation

    51965 Accessories Mounted to the Transom Clamp Bracket Mercury Marine has been made aware that certain aftermarket marine accessories, such as emergency boarding ladders, shallow water anchors, transom wedge kits, and tow sport attaching devices, have been mounted to the boat by use of the same fasteners that secure the outboard to the transom or jack plate.
  • Page 93 OUTBOARD INSTALLATION WARNING Avoid serious injury or death resulting from a loss of boat control. Loose engine fasteners could cause the transom bracket to fail, resulting in a loss of the driver's ability to control the boat. Always ensure that the engine fasteners are tightened to the specified torque.
  • Page 94 OUTBOARD INSTALLATION • The installation must not create interference issues, as would an accessory mounting plate resting in the radius of the transom clamp bracket. Refer to Figure 1. 54624 Figure 1 Minimum clearance 3.175 mm (0.125 in.) Edge of accessory bracket Transom clamp bracket wall Radius Engine supplied mounting fasteners...
  • Page 95 OUTBOARD INSTALLATION UNACCEPTABLE ACCESSORY MOUNTING IMPORTANT: Do not use the fasteners that secure the engine to the boat (either the transom or the jack plate) for any purpose other than securing the engine to the boat. 1. Do not mount an accessory to the transom clamp bracket in an unsupported condition.

  • Page 96: Boat Horsepower Capacity

    OUTBOARD INSTALLATION 3. Do not install wedges or plates between the transom clamp brackets and the transom (or jack plate). Refer to Figure 4. Figure 4 Boat transom or jack plate Transom clamp bracket Wedge/plate 54058 Boat Horsepower Capacity WARNING Exceeding the boat's maximum horsepower rating can cause serious injury or death.

  • Page 97: Fuel System

    OUTBOARD INSTALLATION The remote control connected to the outboard must be equipped with a start in neutral only protection device. This prevents the engine from starting in gear. Fuel System AVOIDING FUEL FLOW RESTRICTION IMPORTANT: Adding components to the fuel supply system (filters, valves, fittings, etc.) may restrict the fuel flow.
  • Page 98 OUTBOARD INSTALLATION The fuel demand valve has a manual release. The manual release can be used (pushed in) to open (bypass) the valve in case of a fuel blockage in the valve. Fuel demand valve ‑ installed in the fuel hose between the fuel tank and primer bulb Manual release Vent/water drain holes...

  • Page 99: Installation Specifications

    OUTBOARD INSTALLATION Installation Specifications 18552 Minimum transom opening Engine centerline for dual engine ‑ 66.0 cm (26 in.) Minimum Transom Opening Single engine 84.8 cm (33‑3/8 in.) Dual engine 151.8 cm (59‑3/4 in.) Lifting the Outboard WARNING Improperly supporting an engine during lifting can result in the engine falling, causing serious injury or death.

  • Page 100: Steering Cable - Starboard Side Routed Cable

    OUTBOARD INSTALLATION 3. Connect a hoist to the lifting eye. 4. Lift the outboard and place it on the boat transom. Lifting Eye 91‑90455‑‑1 Threads into the flywheel to remove the powerhead assembly from the driveshaft housing, or to lift entire engine for removal/installation.

  • Page 101: Steering Link Rod Fasteners

    OUTBOARD INSTALLATION 3. Tighten the nut to the specified torque. 3727 Description lb‑in. lb‑ft 47.5 – Steering Link Rod Fasteners IMPORTANT: The steering link rod that connects the steering cable to the engine must be fastened using a special washer head bolt (P/N 10‑849838) and self‑locking nylon insert locknuts (P/N 11‑826709113).

  • Page 102: Rear-Mounted Steering Rams Or Tie Bars

    OUTBOARD INSTALLATION WARNING Worn, loose, or seized steering components can lead to loss of boat control. Inspect all steering attachment components for wear, lubricate all attachment hardware, and check all fasteners for proper tightness in accordance with the inspection and maintenance schedule. 2767 Special washer head bolt (P/N 10‑849838) Nylon insert locknut (P/N 11‑826709113) ‑...

  • Page 103: Determining Outboard Mounting Height

    OUTBOARD INSTALLATION • Do not install the steering brackets to the powerhead studs (upper studs). • Trim the port and starboard bottom cowls as needed. NOTICE Attaching rear‑mounted steering rams or tie bars to the powerhead studs may cause cylinder distortion and premature engine failure. Attach steering brackets to the correct installation locations.
  • Page 104 OUTBOARD INSTALLATION MOUNTING HEIGHT - FLEET MASTER GEARCASE WARNING Improper installation of an outboard can result in serious injury or death. Do not allow the upper outboard mounting bolts to be closer than 25 mm (1 in.) from the top of the boat transom, not including any shims used to increase transom mounting height.
  • Page 105 OUTBOARD INSTALLATION Item Model Recommended Mounting Height Range 25 in. driveshaft models 533–609 mm (21–24 in.) 30 in. driveshaft models 660–736 mm (26–29 in.) MOUNTING HEIGHT - SPORT MASTER GEARCASE WARNING Improper installation of an outboard can result in serious injury or death. Do not allow the upper outboard mounting bolts to be closer than 25 mm (1 in.) from the top of the boat transom, not including any shims used to increase transom mounting height.

  • Page 106: Drilling Outboard Mounting Holes

    OUTBOARD INSTALLATION IMPORTANT: The recommended mounting height is based on performance testing with a single‑engine application on a hull with no stepped or notched transoms. Your performance results may vary, depending on hull design. For best overall performance on boats with Sport Master gearcases, try to mount the outboard so the propeller shaft centerline is even with the bottom of the boat, as this gearcase is designed for surfacing applications.
  • Page 107 OUTBOARD INSTALLATION 1. Mark four mounting holes on the transom using the transom drilling fixture. Drill guide holes Transom drilling fixture Transom centerline 2757 Transom Drilling Fixture 91‑98234A2 Aids in engine installation by acting as a template for engine mounting holes. 5489 2.

  • Page 108: Fastening The Outboard To The Transom

    OUTBOARD INSTALLATION Fastening the Outboard to the Transom MOUNTING BOLTS Outboard Transom Mounting Hardware ‑ Supplied with Outboard Part Number Part Name Description 8M0071543 Outboard mounting bolt ½‑20 x 5.00 in. long (3.25 in. thread) 826711‑17 Nylon insert locknut ½‑20 28421 Flat washer 1.50 in.
  • Page 109 OUTBOARD INSTALLATION CHECKING BOAT TRANSOM CONSTRUCTION IMPORTANT: Determine the strength of the boat transom. The outboard mounting locknuts and bolts should be able to hold 75 Nm (55 lb‑ft) of torque without the boat transom yielding or cracking. If the boat transom yields or cracks under this torque, the construction of the transom may not be adequate.
  • Page 110 OUTBOARD INSTALLATION FASTENING THE OUTBOARD TO THE TRANSOM IMPORTANT: The transom mounting surface must be flat within 3.17 mm (0.125 in.). No step in the transom mounting surface is allowed. The inside transom mounting bolt washer surface must be flat within 3.17 mm (0.125 in.). 51817 Step (not allowed) Gap between transom clamp and boat transom (not allowed)
  • Page 111 Failure to maintain clearance may damage the transom bracket and cause the transom bracket to fail. Adjustments to the position of the Mercury Marine transom drilling fixture may be required to ensure proper clearance of the transom bracket relief radius area.
  • Page 112 OUTBOARD INSTALLATION NOTE: For a more accurate torque reading, tighten the mounting locknuts rather than the outboard mounting bolts. 40952 0.500 in. diameter outboard mounting bolt (4) 0.875 in. flat washer (4) Nylon insert locknut (4) 1.500 in. flat washer (4) Marine sealer –...

  • Page 113: Electrical, Hoses, Control Cables, And Front Clamp

    OUTBOARD INSTALLATION A decal on the transom bracket reminds the owner to check the fasteners securing the outboard to the transom before each use. 51985 Decal on the transom bracket Electrical, Hoses, Control Cables, and Front Clamp REMOTE WIRING HARNESS Route the remote 14 pin boat harness through the front clamp opening in the bottom cowl.
  • Page 114 OUTBOARD INSTALLATION BATTERY INFORMATION (ALL BATTERIES INCLUDING DTS) WARNING Failure to properly secure the battery leads can result in a loss of power to the Digital Throttle and Shift (DTS) system, leading to serious injury or death due to loss of boat control. Secure the battery leads to the battery posts with hex nuts to avoid loose connections.
  • Page 115 OUTBOARD INSTALLATION BATTERY CABLE CONNECTIONS Single Outboard Red sleeve ‑ positive Black sleeve ‑ negative (–) Cranking battery (-) (-) 15496 Dual Outboards Connect a common ground cable (wire size same as engine battery cables) between negative (–) terminals on starting batteries. 15497 Red sleeve ‑...
  • Page 116 OUTBOARD INSTALLATION HOSE AND TUBING CONNECTIONS Fuel Hose The minimum fuel line inside diameter (I.D.) is 8 mm (5/16 in.), with a separate fuel line/fuel tank pickup for each engine. Fasten the remote fuel hose to the fitting with a hose clamp. Oil Hoses Connect the remote oil hoses to the engine hose connections.
  • Page 117 OUTBOARD INSTALLATION Make the water pressure gauge hose connection to the tubing as shown. 29069 Water pressure tube Speedometer water pickup tube (if required) Coupler Plug Barb hose fitting Speedometer hose or tubing Water pressure tube Remote fuel hose Hose clamp Oil hose with blue stripe Oil hose without blue stripe Cable tie...
  • Page 118 OUTBOARD INSTALLATION a. Move the remote control handle from neutral into forward and advance the handle to the full speed position. Ensure the throttle control lever is touching the throttle control lever stop screw. b. Slowly return the handle back to the neutral detent position. c.
  • Page 119 OUTBOARD INSTALLATION 4. Align the cable end guide against this center mark when installing the cable to the engine. 5. Position the remote control and outboard into neutral position. 6. Slide the anchor pin forward until resistance is felt, then slide the anchor pin toward the rear until resistance is felt.
  • Page 120 OUTBOARD INSTALLATION 3. Secure the shift cable to the anchor pin with the retainer clip. 28749 Cable barrel Shift cable retainer Retainer clip 4. Check the shift cable adjustments as follows: a. Shift the remote control to forward while turning the propeller shaft. If the propeller shaft does not lock in gear, adjust the cable barrel closer to the cable end guide.
  • Page 121 OUTBOARD INSTALLATION Description lb‑in. lb‑ft Throttle cable locknut "b" Tighten, then loosen 1/4 turn 3. Adjust the cable barrel so the installed throttle cable will hold the idle stop screw against the stop. 28751 Barrel sleeve Cable barrel Idle stop screw 4.
  • Page 122 OUTBOARD INSTALLATION 5. Lock the barrel holder in place with the cable latch. 2682 FRONT CLAMP ASSEMBLY INSTALLATION IMPORTANT: There must be sufficient slack in the engine wiring harness, battery cables, fuel hose, and oil hoses, between clamp and engine attachment point, to relieve stress and prevent hoses from being kinked or pinched.
  • Page 123 OUTBOARD INSTALLATION 3. Join the top half of the front clamp with the bottom half. Secure both halves together with cables ties. 29074 Top half of the front clamp Cable ties 4. Secure the front clamp into the bottom cowl with the retainer and two screws.

  • Page 124: Oil Injection Set-Up

    OUTBOARD INSTALLATION Oil Injection Set‑Up FILLING OIL SYSTEM 1. Fill the remote oil tank with the recommended oil listed in the Operation and Maintenance Manual. Tighten the fill cap. Fill cap 2683 2. Remove the cap and fill the engine oil tank with oil. Install the fill cap. Engine oil tank Fill cap 7745...
  • Page 125 OUTBOARD INSTALLATION PRIMING THE OIL INJECTION PUMP Before starting the engine for the first time, prime the oil injection pump. Priming will remove any air that may be in the pump, oil supply hose, or internal passages. 3768 Oil supply hose Oil injection pump IMPORTANT: Fill the engine fuel system with fuel before priming the oil injection pump.

  • Page 126: Engine Well Inlet Cover Installation (Models With Remote Trim Pump)

    OUTBOARD INSTALLATION d. Turn the ignition key switch to the "ON" position for three seconds. This operates the electric fuel pump. 26846 e. Turn the ignition key switch back to the "OFF" position, and squeeze the primer bulb again until it feels firm. f.
  • Page 127 OUTBOARD INSTALLATION • Within easy access to the filler cap. 15870 Transom Trim lines Engine centerline Engine well cover IMPORTANT: The power trim hoses must be able to extend to the rear edge of the transom to connect to the engine. 2.
  • Page 128 OUTBOARD INSTALLATION 4. Install the gasket and cover using four 10‑32 screws, lockwashers, and hex nuts. Cut off excess screw lengths. 15871 Screw (4) Nut (4) Lockwasher (4) Cover Gasket 5. Route the trim pump harness end through the cover and cowl and attach the harness to the pump and the main engine harness.

  • Page 129: Trim In Pin

    OUTBOARD INSTALLATION 8. Connect the trim hoses to the fittings on the transom bracket as shown below. 14628 Power trim down circuit Power trim up circuit Trim In Pin WARNING Operating the boat at high speeds with the outboard trimmed too far under can create excessive bow steer, resulting in the operator losing control of the boat.
  • Page 130 OUTBOARD INSTALLATION However, once on plane, the engine should be trimmed to a more intermediate position to avoid a bow‑down planing condition called plowing. Plowing can cause bow steering or oversteering and inefficiently consumes horsepower. Tilt pin (not included with engine) 2688 Stainless Steel Tilt Pin 17‑49930A 1...

  • Page 131: Maintenance Log

    MAINTENANCE LOG Maintenance Log Record all maintenance performed on your outboard here. Be sure to save all work orders and receipts. Date Maintenance Performed Engine Hours...

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300 xs optimax

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