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Mercury Jet 25 Manual

2-stroke supplement
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Summary of Contents for Mercury Jet 25

  • Page 3: Table Of Contents

    TABLE OF CONTENTS WARRANTY Outboard Limited Warranty United States, Canada, Europe and Confederation of Independent States..........1 GENERAL INFORMATION Before Operating Your Outboard..........5 Protecting People In The Water........... 6 Safe Boating Suggestions............7 Specifications................9 Components................10 OPERATION Lubricating the Driveshaft Bearing..........11 Operating In Freezing Temperatures......... 11 Pre‑Starting Check List..............11 Operating In Salt Water Or Polluted Water........
  • Page 4 TABLE OF CONTENTS TROUBLESHOOTING Engine Over‑Speed (Excessive RPM)........24 Performance Loss..............24 ENGINE INSTALLATION Determining the Mounting Height of the Outboard ....25 Water Testing................26...

  • Page 5: Outboard Limited Warranty United States, Canada, Europe And Confederation Of Independent States

    WARRANTY COVERAGE: Warranty coverage is available only to retail customers that purchase from a Dealer authorized by Mercury Marine to distribute the product in the country in which the sale occurred, and then only after the Mercury Marine specified pre–delivery inspection process is completed and documented.
  • Page 6 WHAT MERCURY WILL DO: Mercury’s sole and exclusive obligation under this warranty is limited to, at our option, repairing a defective part, replacing such part or parts with new or Mercury Marine certified remanufactured parts, or refunding the purchase price of the Mercury product. Mercury reserves the right to improve or modify products from time to time without assuming an obligation to modify products previously manufactured.
  • Page 7 No individual or entity, including Mercury Marine authorized dealers, has been given authority by Mercury Marine to make any affirmation, representation or warranty regarding the product, other than those contained in this limited warranty, and if made, shall not be enforceable against Mercury Marine.
  • Page 8 WARRANTY DISCLAIMERS AND LIMITATIONS: THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY DISCLAIMED. TO THE EXTENT THAT THEY CANNOT BE DISCLAIMED, THE IMPLIED WARRANTIES ARE LIMITED IN DURATION TO THE LIFE OF THE EXPRESS WARRANTY. INCIDENTAL AND CONSEQUENTIAL DAMAGES ARE EXCLUDED FROM COVERAGE UNDER THIS WARRANTY.

  • Page 9: General Information

    GENERAL INFORMATION Before Operating Your Outboard Read this manual carefully. Learn the difference in handling characteristics between a jet drive boat and a propeller driven boat. If you have any questions, contact your dealer. STEERING AT LOW SPEEDS Unlike propeller driven boats, the jet drive boat tends to lose steering control as less water is drawn in and expelled.

  • Page 10: Protecting People In The Water

    GENERAL INFORMATION CAUTION Indicates a hazardous situation which, if not avoided, could result in minor or moderate injury. NOTICE Indicates a situation which, if not avoided, could result in engine or major component failure. IMPORTANT: Identifies information essential to the successful completion of the task.

  • Page 11: Safe Boating Suggestions

    GENERAL INFORMATION WHILE BOAT IS STATIONARY WARNING Avoid injury resulting from contacting the rotating impeller or having hair, clothing, or loose objects drawn into the water intake and wrapping around the impeller shaft. Stay away from the water intake and never insert an object into the water intake or water outlet nozzle when the engine is running.
  • Page 12 GENERAL INFORMATION Prepare other boat operators. Instruct at least one other person on board in the basics of starting and operating the jet drive, and boat handling, in case the driver becomes disabled or falls overboard. Passenger boarding. Stop the engine whenever passengers are boarding, unloading, or are near the back (stern) of the boat.

  • Page 13: Specifications

    $500.00 or 4) there is complete loss of the boat. Seek further assistance from local law enforcement. Specifications Model Jet 25 Jet power 19 kW (25 hp) Horsepower 22 kW (30 hp) Engine idle RPM 950 +/‑...

  • Page 14: Components

    GENERAL INFORMATION Components 29515 Top cowl Water intake housing Manual start handle Reverse gate Throttle grip Water outlet Gear shift Driveshaft housing Lanyard cord -Engine stop switch Reverse lock lever Choke knob Tilt pin Fuel hose connector Jet drive housing...

  • Page 15: Operation

    OPERATION Lubricating the Driveshaft Bearing Before each use, lubricate the driveshaft bearing. Refer to Maintenance - Lubricating the Driveshaft Bearing. 27490 Operating In Freezing Temperatures If there is a chance of ice forming on the water, the jet drive should be removed and drained completely of water.

  • Page 16: Operating In Salt Water Or Polluted Water

    Wash down the outboard exterior and flush out the exhaust outlet of the jet drive with fresh water after each use. Each month, spray Mercury Precision or Quicksilver Corrosion Guard on external metal surfaces. Operating In Shallow Water The life of the impeller and water intake can be greatly increased by avoiding the intake of sand and gravel.

  • Page 17: How The Jet Drive Operates

    OPERATION How the Jet Drive Operates A jet driven boat has substantially different handling characteristics compared to a propeller driven boat. It is recommended that the operator adjusts to these characteristics by experimenting in open water at both high and low speeds. The driveshaft driven impeller draws water up through the water intake and then redirects it at a high pressure through the water outlet nozzle to create forward thrust.

  • Page 18: Stopping The Boat In An Emergency

    OPERATION WARNING Avoid injury resulting from contacting the rotating impeller or having hair, clothing, or loose objects drawn into the water intake and wrapping around the impeller shaft. Stay away from the water intake and never insert an object into the water intake or water outlet nozzle when the engine is running.

  • Page 19: Mooring The Boat

    OPERATION WARNING Steering the vessel in a tight turn can result in loss of boat control. In some cases, the boat can spin out or roll over, causing serious injury or death. Avoid steering beyond the capabilities of the vessel, especially at high speeds. WARNING A loss or reduction in water jet thrust will directly affect boat directional control, and may result in property damage, personal...

  • Page 20: Water Intake Blockage

    OPERATION Water Intake Blockage WARNING A rotating impeller could cause injury if contact is made with hands, clothing, or tools. To avoid injury, keep hands and clothing away from the inlet or outlet of the jetdrive, regardless of whether the boat is in the water. Secure tools and loose items to avoid being struck by projectiles as a result of contact with the rotating impeller, and to prevent damage to the impeller.

  • Page 21: Maintenance

    MAINTENANCE Worn/Dull Impeller The intake of gravel through the pump can round off and wear the leading edges of the impeller. Some conditions that could be experienced from a worn/dull impeller are as follows: • Noticeable performance loss, especially on acceleration •...

  • Page 22: Replaceable Jet Drive Shear Key

    MAINTENANCE As the blades wear, shims located in the stack outside of the impeller can be transferred behind the impeller. This will move the impeller further down into the tapered liner to reduce the clearance. 29080 Shims Clearance between impeller edge and liner Check the impeller clearance by sliding a feeler gauge through the intake grate and measure the clearance between the impeller edge and liner.

  • Page 23: Impeller Removal And Installation

    MAINTENANCE Impeller Removal and Installation WARNING Rotating the driveshaft may cause the engine to crank over and start. To prevent this type of accidental engine starting and possible serious injury caused from being struck by a rotating impeller, always turn the ignition key or lanyard stop switch to the "OFF"...

  • Page 24: Shift Link Rod Adjustment

    MAINTENANCE 5. Straighten the bent tabs on the impeller nut retainer and remove the impeller nut. 29082 Tabs Impeller nut 6. Pull the impeller straight off the shaft. If the impeller is tight, use a hammer and a block of wood to rotate the impeller clockwise on the shaft until the keyway is directly above the flat on the shaft.

  • Page 25: Corrosion Control Anode

    MAINTENANCE CHECKING SHIFT LINK ROD ADJUSTMENT Check the shift link rod adjustment in forward shift position. The correct adjustment will position the shift cam far enough on the roller in order to lock the reverse gate into forward position. The reverse gate should not be able to be forced up towards neutral.

  • Page 26: Lubricating The Driveshaft Bearing

    MAINTENANCE An anode is located on the water intake housing. An anode requires periodic inspection, especially in salt water 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.
  • Page 27 MAINTENANCE 3. Reconnect the vent hose onto the grease fitting after greasing. 27491 Grease fitting Vent hose NOTE: After 30 hours of operation, pump in extra grease to purge out any moisture. Visually inspecting the purged grease at this time will give an indication of conditions inside the bearing housing.

  • Page 28: Troubleshooting

    TROUBLESHOOTING Engine Over‑Speed (Excessive RPM) POSSIBLE CAUSES • Outboard mounted too high on the transom. • Worn jet pump impeller or liner. • Incorrect jet pump impeller clearance adjustment. • Tilting the outboard out beyond a vertical position. • Cavitation of the impeller due to rough water or obstruction in the boat hull.

  • Page 29: Engine Installation

    ENGINE INSTALLATION Determining the Mounting Height of the Outboard The following outboard mounting height settings will work good for most applications, however, because of different boat/hull designs, the setting should be rechecked by test running the boat. Refer to Water Testing. •...

  • Page 30: Water Testing

    ENGINE INSTALLATION BOATS WITH A FLAT BOTTOM HULL 1. Place (center) the outboard on the boat transom. Set the height of the outboard on the boat transom so that the front edge of the water intake housing is in line with the bottom of the boat as shown.
  • Page 31 ENGINE INSTALLATION If cavitation still exists after lowering the outboard, it may be helpful to seek advice from the boat manufacturer. Another option to further reduce cavitation is a rough water plate. A rough water plate may be helpful in reducing cavitation when running in windy, rough water conditions where air is sucked into the water intake when jumping waves.

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