Mercury jet 20 Manual Download Page 53

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MAINTENANCE

Shift the outboard to forward gear and reduce engine speed to idle. Ensure the primer/fast idle knob is

pushed all the way in and turned to the slowest idle speed.

Adjust the idle speed screw to obtain the recommended engine idle speed. Refer to General Information ‑

Specification.

ob01425

HIGH SPEED MIXTURE ADJUSTMENT

The carburetor is equipped with a standard size high speed fixed jet that is replaceable for operation at higher

elevations.

Submerged Outboard

A submerged outboard will require service within a few hours by an authorized dealer once the outboard is

recovered from the water. This immediate attention by a servicing dealer is necessary once the engine is exposed

to the atmosphere to minimize internal corrosion damage to the engine.

Summary of Contents for jet 20

Page 1: ...ne Fond du Lac WI USA or Marine Power Europe Inc Park Industriel de Petit Rechain Belgium complies with the requirements of the following directives and standards as amended Recreational Craft Directive 94 25 EC Owner s manual A 2 5 ISO 10240 Handling characteristics A 4 ISO 8665 Outboard engine starting A 5 1 4 ISO 11547 Fuel tanks A 5 2 2 ISO 13591 ISO 8469 General steering system ABYC P 17 Safe...

Page 2: ...ii Patrick C Mackey President Mercury Marine Fond du Lac WI USA European Regulations Contact Regulations and Product Safety Department Mercury Marine Fond du Lac WI USA ...

Page 3: ...erating Your Outboard 8 Boat Horsepower Capacity 8 Lanyard Stop Switch 9 Stopping the Boat in an Emergency 10 Protecting People In The Water 10 Wave And Wake Jumping 11 Exhaust Emissions 11 Selecting Accessories For Your Outboard 13 Safe Boating Suggestions 13 Recording Serial Number 14 Jet 20 Specifications 14 Installation Installing Outboard 15 Transporting Carrying Outboard 16 Trailering Boat O...

Page 4: ...gine 28 Gear Shifting 30 Stopping The Engine 30 Emergency Starting 31 Maintenance Outboard Care 33 EPA Emissions 33 Inspection And Maintenance Schedule 34 Top Cowl Removal And Installation 34 Fuel System 35 Exterior Care 36 Worn Dull Impeller 36 Impeller Clearance Adjustment 37 Impeller Removal and Installation 38 Shift Link Rod Adjustment 42 Lubrication Points 43 Spark Plug Inspection and Replace...

Page 5: ...CONTENTS v Engine Over Speed Excessive RPM 49 Owner Service Assistance Local Repair Service 50 Service Away From Home 50 Parts And Accessories Inquiries 50 Service Assistance 50 Mercury Marine Service Offices 50 ...

Page 6: ...vi ...

Page 7: ... the Federal Safety Act be required 2 To be eligible for warranty coverage the product must be registered with Mercury Marine At the time of sale the dealer should complete the warranty registration and immediately submit it to Mercury Marine via MercNET E mail or mail Upon receipt of this warranty registration Mercury Marine will record the registration 3 Upon processing the warranty registration...

Page 8: ...ration date Unexpired warranty coverage can be transferred from one recreational use customer to a subsequent recreational use customer upon proper re registration of the product Unexpired warrant coverage cannot be transferred either to or from a commercial use customer CONDITIONS THAT MUST BE MET IN ORDER TO OBTAIN WARRANTY COVERAGE Warranty coverage is available only to retail customers that pu...

Page 9: ...arranty and if made shall not be enforceable against Mercury Marine For additional information regarding events and circumstances covered by this warranty and those that are not see the Warranty Coverage section of the Operation and Maintenance Manual incorporated by reference into this warranty DISCLAIMERS AND LIMITATIONS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURP...

Page 10: ...his limited warranty does not cover routine maintenance items tune ups adjustments normal wear and tear damage caused by abuse abnormal use use of a propeller or gear ratio that does not allow the engine to run in its recommended wide open throttle RPM range see the Operation and Maintenance Manual operation of the product in a manner inconsistent with the recommended operation duty cycle section ...

Page 11: ...rformed including without limitation the replacement of sacrificial anodes use of specified lubricants and touch up of nicks and scratches in order to maintain warranty coverage Mercury Marine reserves the right to make warranty coverage contingent upon proof of proper maintenance WHAT MERCURY WILL DO Mercury s sole and exclusive obligation under this warranty is limited to at our option repairing...

Page 12: ...YOU MAY ALSO HAVE OTHER LEGAL RIGHTS WHICH VARY FROM STATE TO STATE AND COUNTRY TO COUNTRY Warranty Coverage And Exclusions The purpose of this section is to help eliminate some of the more common misunderstandings regarding warranty coverage The following information explains some of the types of services that are not covered by warranty The provisions set forth following have been incorporated b...

Page 13: ...r preparing for racing or other competitive activity or operating with a racing type lower unit 11 Engine noise does not necessarily indicate a serious engine problem If diagnosis indicates a serious internal engine condition which could result in a failure condition responsible for noise should be corrected under the warranty 12 Lower unit and or propeller damage caused by striking a submerged ob...

Page 14: ...d and reverse thrust will minimize boat movement the boat may tend to move slowly forward or backward This is normal for a direct drive jet driven boat The operator should be aware of this and use caution whenever the engine is running Safety and operating information that is practiced along with using good common sense can help prevent personal injury and product damage This manual as well as saf...

Page 15: ...is desired to have a shorter lanyard wrap the lanyard around the operator s wrist or leg or tie a knot in the lanyard ob00310 a b a Lanyard cord b Lanyard stop switch Read the following Safety Information before proceeding Important Safety Information The purpose of a lanyard stop switch is to stop the engine when the operator moves far enough away from the operator s position to activate the swit...

Page 16: ...ected over the bow and possibly struck by the jet drive Loss of power and directional control in heavy seas strong current or high winds Loss of control when docking Stopping the Boat in an Emergency A jet powered boat has emergency stopping capability unique to this form of propulsion WARNING Using the emergency stopping capability of the jet drive will slow down the boat in an emergency However ...

Page 17: ...veer violently in a new direction Such a sharp change in direction can cause occupants to be thrown out of their seats or out of the boat WARNING Avoid serious injury or death from being thrown within or out of a boat when it lands after jumping a wave or wake Avoid wave or wake jumping whenever possible Instruct all occupants that if a wake or wave jump occurs get low and hang on to a boat hand h...

Page 18: ...losed cabins or cockpits with insufficient ventilation may draw in carbon monoxide Install one or more carbon monoxide detectors in your boat Although the occurrence is rare on a very calm day swimmers and passengers in an enclosed area of a stationary boat that contains or is near a running engine may be exposed to a hazardous level of carbon monoxide WHILE BOAT IS STATIONARY ob00317 a b a Runnin...

Page 19: ...s of boat control or sudden boat movement could cause a person to be thrown overboard or into the boat Never be under the influence of alcohol or drugs while boating it is the law Alcohol or drug use impairs judgment and greatly reduces the ability to react quickly Prepare other boat operators Instruct at least one other person on board in the basics of starting and operating the jet drive and boa...

Page 20: ...nt to record this number for future reference The serial number is located on the outboard as shown Serial Number H P L B XXXX XX XXXXXXXX XXXX a b c d e ob01356 K W K G MAX RPM a Serial number b Model year c Model designation d Year manufactured e Certified Europe Insignia as applicable Jet 20 Specifications Models 20 Jet Power 20 Engine Horsepower 25 Full Throttle RPM Range 5000 6000 RPM Idle Sp...

Page 21: ...er installation and good performance If you install the outboard yourself follow instructions in the Outboard Jet Installation Manual which is provided with the outboard 1 Place outboard on center line of transom Tighten transom clamp handles ob00503 2 To prevent loss of outboard fasten outboard by drilling two 7 9 mm 5 16 in holes through the transom using transom clamp holes as a template Fasten...

Page 22: ...or railroad crossings driveways and trailer bouncing Transporting Outboard When Removed From Boat 1 With the outboard still in the water disconnect the fuel line from the outboard and run engine until it stops This will drain fuel from the carburetor Remove outboard from the boat and hold upright until all cooling water is drained out 2 Lay the outboard down horizontally on its tiller handle side ...

Page 23: ...om tank This will close the air vent and prevent escape of fuel or vapors from tank 2 Install tether cap over the fuel line connector stem This will protect the connector stem from being accidently pushed in thus allowing fuel or vapor to escape F ob00326 a b a Connector stem b Tether cap ...

Page 24: ...r alcohol from the gasoline in the fuel tank The fuel system components on your Mercury Marine engine will withstand up to 10 alcohol content in the gasoline We do not know what percentage your boat s fuel system will withstand Contact your boat manufacturer for specific recommendations on the boat s fuel system components fuel tanks fuel lines and fittings Be aware that gasolines containing alcoh...

Page 25: ...he full amount of oil along with approximately one gallon of gasoline into an approved container Shake the two together until they are thoroughly mixed Add the remainder of gasoline and shake container to ensure mixing Filling Fuel Tank WARNING Avoid serious injury or death from a gasoline fire or explosion Always stop the engine and do not smoke or allow open flames or sparks in the area while fi...

Page 26: ...the knob out supplies a small amount of fuel to the engine for cold starting Rotate knob to adjust idle speed after engine warms up ob01384 Lanyard Lanyard Stop Switch Refer to General Information Lanyard Stop Switch ob00350 Engine Stop Switch Push in to stop engine ob00361 Throttle Grip Friction Knob Turn friction knob to set and maintain the throttle at desired speed Turn knob clockwise to tight...

Page 27: ...peed position in order to start engine Throttle Grip Controls engine speed ob00543 WARNING Avoid possible serious injury or death from loss of boat control Maintain sufficient steering friction to prevent the outboard from steering into a full turn if the tiller handle or steering wheel is released Steering Friction Adjustment Adjust this lever to achieve the desired steering friction drag on the ...

Page 28: ...G TO FULL UP POSITION 1 Stop the engine Shift the outboard into forward gear 2 Take hold of the top cowl grip and raise outboard to the full up position ob01387 3 Move the tilt lock lever to the lock position ob01388 LOWERING TO RUN POSITION 1 Lift outboard and release tilt lock lever Lower outboard ...

Page 29: ...provided Proper adjustment allows the boat to achieve optimum performance stability and minimize steering effort ob01429 a a Tilt pin 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 This allows the boat to be driven parallel to the water Arrange passengers and load in the boat so the weight is distributed evenly...

Page 30: ...t in use 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 at High Elevations IMPORTANT To prevent serious damage to the engine caused by a lean fuel mixture do not operate the outboard if the jets were changed for high elevation at ...

Page 31: ...d to move slowly forward or backward This is normal for a direct drive jet driven boat The operator should be aware of this and use caution whenever the engine is running 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 ...

Page 32: ...y to take evasive action is dependent on sufficient water jet thrust to control the boat While steering the boat at engine speeds above idle the boat will respond quickly but due to the relatively flat bottom hulls and lack of a gearcase in the water the boat will tend to skid on turns Turns must be started early and use sufficient power to maintain steering control Mooring The Boat Be sure to til...

Page 33: ...ote fuel line to the outboard Make sure connector is snapped into place ob01393 CAUTION Never start or operate your outboard even momentarily without water circulating through all the cooling water intake holes in the gearcase to prevent damage to the water pump running dry or overheating of the engine 2 Make sure the driveshaft bearing on the jet drive is lubricated Refer to Maintenance Lubricati...

Page 34: ...type fuel tanks ob00348 2 Squeeze the fuel line primer bulb several times until it feels firm ob00349 3 Set the lanyard stop switch to RUN position Refer to General Information Lanyard Stop Switch ob00350 4 Set the throttle grip to start position ob00543 5 Side Handle Gear Shift Models Set the gear shift to neutral N position R F ob01385 N 6 Turn primer idle speed knob full clockwise to increase e...

Page 35: ...apidly to crank the engine Allow rope to return slowly Repeat until engine starts ob01383 NOTE Starting flooded engine Push in the primer idle speed knob and turn full clockwise Continue to crank the engine for starting 9 Push in the primer idle speed knob after engine starts If engine begins to stall reprime until engine is running smoothly ob01398 10 Turn the primer idle speed knob counterclockw...

Page 36: ...out of the indicator hole ob00331 Gear Shifting NOTE In neutral the impeller continues to rotate Although the approximate balancing of forward and reverse thrust will minimize boat movement the boat may tend to move slowly forward and backward This is normal for a direct drive jet driven boat The operator should be aware of this and use caution whenever the engine is running The outboard has three...

Page 37: ...WARNING When using the emergency starter rope to start engine the start at idle speed protection is inoperative Make sure to have the engine speed set at slow and the outboard gear shift positioned in neutral to prevent outboard from starting in gear Sudden unexpected acceleration could result in serious injury or death 2 Pry the fuel filter out of its mount ob01401 3 Disconnect linkage from rewin...

Page 38: ... cause serious injury Keep your hands hair clothing tools and other objects away from engine when starting or running the engine Do not attempt to reinstall the rewind starter assembly or top cowl when engine is running 5 Tie one end of the starter rope around screwdriver tool provided and tie a knot in other end 6 Place the starter rope knot into the flywheel notch and wind the rope clockwise aro...

Page 39: ...uld result in personal injury death or product failure EPA Emissions EMISSION CERTIFICATION LABEL An emission certification label showing emission levels and engine specifications directly related to emissions is placed on the engine at time of manufacture EMISSION CONTROL INFORMATION TIMING IN DEGREES FAMILY FEL cc IDLE SPEED hp GAP g kW h Standard spark plug Suppressor spark plug This engine con...

Page 40: ...equently when used in salt water See Lubrication Points Inspect and clean spark plugs See Spark Plug Inspection and Replacement Check engine fuel filter for contaminants See Fuel System Check carburetor adjustments if required See Carburetor Adjustments Lubricate splines on the driveshaft 1 Remove engine deposits with Quicksilver or Mercury Precision Power Tune Engine Cleaner Clean fuel tank pick ...

Page 41: ...ely Material used to contain spillage must be disposed of in an approved receptacle Any fuel system service must be performed in a well ventilated area Inspect any completed service work for sign of fuel leakage FUEL LINE INSPECTION Visually inspect the fuel line and primer bulb for cracks swelling leaks hardness or other signs of deterioration or damage If any of these conditions are found the fu...

Page 42: ... squeezing the primer bulb until firm forcing fuel into the filter Exterior Care Your outboard is protected with a durable baked enamel finish Clean and wax often using marine cleaners and waxes 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 Noticeab...

Page 43: ...dge and liner Operating the jet drive in waters that contain sand and gravel can cause wear to the impeller blades and the clearance will start to exceed 0 8 mm 0 03 in 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 ob01410 b a a Shims b Clearance be...

Page 44: ...serious injury caused from being struck by a rotating impeller always shift outboard to neutral position and remove spark plug leads when servicing the propeller REMOVAL 1 Shift outboard to neutral N position R F ob01385 N 2 Remove spark plug leads to prevent engine from starting ob00375 3 Remove the water intake housing that is fastened with six screws ob01411 4 Straighten the bent tabs on the im...

Page 45: ...of wood to rotate the impeller clockwise on the shaft until the keyway is directly above the flat on the shaft This will free the jammed key and allow removal INSTALLATION 1 Grease the driveshaft shear key and impeller bore 2 Place the plastic sleeve inside the impeller and install impeller shear key shims nut retainer and impeller nut ...

Page 46: ...the nut remove the nut and turn the retainer over and re tighten the nut again 4 Temporarily reinstall the water intake housing in order to check for impeller clearance The clearance between the impeller and liner should be 0 08 mm 0 03 in Shim washers can be transferred to either side of the impeller to raise or lower the impeller to the correct clearance setting The water intake housing can be s...

Page 47: ...ly Quicksilver or Mercury Precision Anti Corrosion Grease around the entire mounting flange on the water intake housing and also to the threads on the six mounting bolts Tube Ref No Description Where Used Part No 94 Anti Corrosion Grease Water intake housing mounting flange and mounting bolts 92 802867Q1 6 Reinstall the water intake housing with six bolts Check clearance around the impeller to ens...

Page 48: ...occupants to be thrown within the boat or even out of the boat This action may result in serious injury or death 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 toward...

Page 49: ...ease gun provided until excess grease starts to exit the vent hose iii Reconnect the vent hose onto the grease fitting after greasing ob01416 a b a Grease fitting b 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 A gradual increase in moistur...

Page 50: ...cket transom clamp screws tilt tube throttle shift cable 92 802859Q1 Steering Friction Adjustment Shaft Tiller Handle Models Lubricate fitting Swivel Bracket Lubricate fitting ob01417 a b a Steering friction adjustment shaft b Swivel bracket Transom Clamp Screws Lubricate threads ob01418 Tilt Tube Lubricate fittings ob01419 ...

Page 51: ...parks Sparks can ignite fuel vapors under the engine cowl To avoid damaging spark plug boots do not use any sharp object or metal tool such as pliers screwdriver etc to remove spark plug boots 1 Remove the spark plug leads Twist the rubber boots slightly and pull off ob00375 2 Remove the spark plugs to inspect Replace spark plug if electrode is worn or the insulator is rough cracked broken blister...

Page 52: ...ecurely to dock start engine and allow it to warm up 4 Shift the outboard to forward gear while maintaining idle speed 5 Turn the slow speed mixture screw slowly in until the engine starts to misfire or stall due to a lean mixture Note the position of the screw slot ob01423 6 Turn the slow speed mixture screw slowly out until the engine starts to load up or fire unevenly due to a rich mixture Note...

Page 53: ... Specification ob01425 HIGH SPEED MIXTURE ADJUSTMENT The carburetor is equipped with a standard size high speed fixed jet that is replaceable for operation at higher elevations Submerged Outboard A submerged outboard will require service within a few hours by an authorized dealer once the outboard is recovered from the water This immediate attention by a servicing dealer is necessary once the engi...

Page 54: ...ne for ten minutes to fill the engine fuel system 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 Use...

Page 55: ...s fouled or defective Refer to Maintenance section Engine Runs Erratically POSSIBLE CAUSES Spark plugs fouled or defective Refer to Maintenance section Incorrect setup and adjustments Fuel is being restricted to the engine Engine fuel filter is obstructed Refer to Maintenance section Fuel tank filter obstructed Stuck anti siphon valve on built in fuel tank Fuel line is kinked or pinched Fuel pump ...

Page 56: ...very important to your dealer and to us If you ever have a problem question or concern about your outboard product contact your dealer or any authorized Mercury Marine dealership If additional assistance is required take these steps 1 Talk with the dealership s sales manager or service manager If this has already been done then contact the owner of the dealership 2 Should you have a question conce...

Page 57: ...striel de Petit Rechain B 4800 Verviers Belgium Fax 32 87 31 19 65 Mexico Central America South America Caribbean Telephone 954 744 3513 Mercury Marine 11650 Interchange Circle North Miramar FL 33025 U S A Fax 954 744 3535 Japan Telephone 81 053 423 2500 Mercury Marine Japan Anshin cho 283 1 Hamamatsu Shizuoka ken Japan 435 0005 Japan Fax 81 053 423 2510 Asia Singapore Telephone 5466160 Mercury Ma...

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