SERVICE MANUAL NUMBER 28 TROUBLESHOOTING IMPORTANT

1C

TROUBLESHOOTINGSERVICE MANUAL NUMBER 28

90-863160--1 JUNE 2003 Page 1C-1

IMPORTANT INFORMATIONSection 1C - Troubleshooting

Table of Contents

Troubleshooting 1C-3. . . . . . . . . . . . . . . . . . . . . Sterndrive Unit Will Not Slide Into Bell Housing 1C-3. . . . . . . . . . . . . . Sterndrive Unit Does Not Shift Into Gear; Remote Control Shift Handle Moves 1C-3. . . . . . . . . . . . . . . . Sterndrive Unit Does Not Shift Into Gear; Remote Control Shift Handle Does Not Move 1C-4. . . . . . . . . . . . . Sterndrive Unit Shifts Hard 1C-4. . . . . . . . . . . Sterndrive Unit In Gear, Will Not Shift Out Of Gear 1C-4. . . . . . . . . . . Gear Housing Noise 1C-5. . . . . . . . . . . . . . . . Drive Shaft Housing Noise 1C-5. . . . . . . . . . .

Power Shift 1C-8. . . . . . . . . . . . . . . . . . . . . . . . . . System Does Not React 1C-8. . . . . . . . . . . . . System Binds 1C-8. . . . . . . . . . . . . . . . . . . . . .

Performance Troubleshooting 1C-9. . . . . . . . Low WOT Engine RPM 1C-9. . . . . . . . . . . . . . High WOT Engine RPM 1C-9. . . . . . . . . . . . . Propeller Ventilating/Cavitating 1C-9. . . . . . . Poor Boat Performance And/Or Poor Maneuverability - Bow Too Low 1C-10. . . . . . . . . . . . . . . . . . . . Poor Boat Performance And/Or Poor Maneuverability - Bow Too High 1C-10. . . . . . . . . . . . . . . . . . .

Power Steering 1C-11. . . . . . . . . . . . . . . . . . . . . Hard Steering - Helm And Cable 1C-11. . . . . Hard Steering (Engine Running) - Power Steering System 1C-11. . . . . . . . . . . Power Steering System External Fluid Leaks 1C-11. . . . . . . . . . . . . . . . . . . . . . .

Compact Hydraulic Steering 1C-12. . . . . . . . . Important Information 1C-12. . . . . . . . . . . . . . Helm Becomes Jammed During Filling 1C-12. . . . . . . . . . . . . . . . . . . . . System Difficult To Fill 1C-12. . . . . . . . . . . . . . Steering Hard To Turn 1C-12. . . . . . . . . . . . . . Helm Unit Bumpy - Requires Too Many Turns 1C-13. . . . . . . . . . . . . . . . . . .

Power Trim Electrical System 1C-13. . . . . . . . Power Trim Pump Motor Will Not Operate In The OUT/UP Or IN/DOWN Direction - Solenoids Do Not Click 1C-13. . . . . . . . . . . . . . . . . . . . . . Power Trim Pump Motor Will Not Operate In The OUT/UP Or IN/DOWN Direction - Both Solenoids Click 1C-14. . . . . . . . . . . . . Power Trim Pump Motor Operates In The OUT/UP Direction, But Not In The IN/DOWN Direction - IN/DOWN Solenoid Does Not Click 1C-14. Power Trim Pump Motor Operates In The OUT/UP Direction, But Not In The IN/DOWN Direction - IN/DOWN Solenoid Clicks 1C-15. . . . . . . . Power Trim Pump Motor Operates In The IN/DOWN Direction, But Not In The OUT/UP Direction - Both Trim And Trailer Switches Inoperative - OUT/UP Solenoid Does Not Click 1C-15. . . . . . . . . . . . . . . . . . . . Power Trim Pump Motor Operates In The IN/DOWN Direction, But Not In The OUT/UP Direction - Both Trim And Trailer Switches Inoperative - OUT/UP Solenoid Clicks 1C-15. . . . . . . . . . Trim Control OUT/UP Trim Switch Inoperative - Trailer Switch Operates 1C-16. . . . . . . . . . . Trim Control Trailer Switch Inoperative - Trim OUT/UP Switch Functions 1C-16. . . . Trim System Functions While Unattended 1C-16. . . . . . . . . . . . . . . . .

Power Trim System Wiring Diagram 1C-17. .

TROUBLESHOOTING SERVICE MANUAL NUMBER 28

Page 1C-2 90-863160--1 JUNE 2003

Table of Contents (continued)

Power Trim Hydraulic System 1C-18. . . . . . . . Sterndrive Unit Cannot Be Trimmed OUT/UP, Trims Slowly Or With Jerky Movements 1C-18. . . . . . . . . . Sterndrive Unit Will Not Stay In Trimmed OUT/UP Position 1C-18. . . . . . . Sterndrive Unit Trails OUT/UP OnDeceleration Or When Shifting Into Reverse - Unit Thumps When Shifting 1C-18. . . . . . . . . . . . . . . . . . . . Oil Foams Out Of Pump Fill/Vent Screw 1C-19. . . . . . . . . . . . . . . . . . . . Sterndrive Unit Cannot Be Lowered From UP Position Or Lowers With Jerky Movements 1C-19. . . . . . . . . . . . . Sterndrive Unit Will Not Stay In Full UP Position For Extended Periods 1C-19. . . . . . . . . . . . . . . . . Sterndrive Will Not Stay In The Trimmed OUT/UP Position When Underway 1C-20. . . . . . . . . . . . . . . . . . Sterndrive Unit Trails OUT/UP OnDeceleration Or When Shifting Into Reverse - Unit Thumps When Shifting 1C-20. . . . . . . . . . . . . . . . . . . . Trim Motor Operates But Does Not Pump Oil 1C-20. . . . . . . . . . . . . . . . . . . . . Trim Pump Operates Slowly In Both Directions 1C-20. . . . . . . . . . . Trim Pump Operates Slowly With A Laboring Sound 1C-20. . . . . . . . . . . .

Power Trim Hydraulic Schematic 1C-21. . . . . Corrosion Protection 1C-22. . . . . . . . . . . . . . . .

Corrosion On Underwater Parts, Without MerCathode Or Impressed Current Protection 1C-22. . . . . . . Corrosion On Underwater Parts, With MerCathode Or Impressed Current Protection - Sterndrive Unit Corroding 1C-23. . . . . . . . . . . . . . . . . . . . Corrosion On Underwater Parts, With MerCathode Or Impressed Current Protection - Sterndrive Unit Over-protected 1C-25. . . . . . . . . . . . . . .

Sterndrive Over-Protected 1C-25. . . . . . . Testing Procedure for Corrosion Protection 1C-26. . . . . . . . . . . . . . .

Corrosion Symptoms 1C-26. . . . . . . . . . . . MerCathode Controller 1C-27. . . . . . . . . . . .


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Troubleshooting

This section is a guide for performance and product troubleshooting. Referrals to specificsections of this manual are made where special tests or repair procedure are to beperformed.

Because of the relationship between power package components (engine and sterndrive),it will be necessary in some cases to simultaneously refer to the appropriate MercuryMerCruiser Engine Service Manual for further troubleshooting information.

Effective troubleshooting is best enhanced by:

• Personal product knowledge and experience of the trained mechanic/technician

• Allowing adequate time for testing and analysis

• Utilizing these charts as a guide, a starting point

Sterndrive Unit Will Not Slide Into Bell Housing

Cause Special Instructions

U-joint shaft splines not aligned withengine coupler splines.

Rotate propeller shaftCOUNTERCLOCKWISE to alignsplines.

Engine not aligned. Check engine alignment.

Gimbal bearing not properly installed.Check engine alignment to determine ifgimbal bearing is angled or improperlyinstalled in gimbal housing.

Damaged U-joint shaft splines and/orengine coupler splines.

Inspect and replace if necessary.

Sterndrive Unit Does Not Shift Into Gear; Remote Control Shift Handle MovesNOTE: For additional information on troubleshooting, refer to Section 2A -Troubleshooting Shift Problems.


Shift cables improperly adjusted. Adjust shift cables.

Shift cables not connected. Install and adjust shift cables.

Inner core wire broken or loose. Reconnect or replace inner core wire.


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Sterndrive Unit Does Not Shift Into Gear; Remote Control Shift Handle DoesNot Move

NOTE: For additional information on troubleshooting, refer to Section 2ATroubleshooting Shift Problems.


Control box not properly assembled. Properly reassemble control box.

Broken or damaged linkage in controlbox.

Repair linkage.

Controls improperly adjusted, cable endguide hitting brass barrel.

Adjust shift cables.

Sterndrive Unit Shifts HardNOTE: For additional information on troubleshooting, refer to Section 2A -Troubleshooting Shift Problems.


Shift cables improperly adjusted. Adjust shift cables.

Damaged remote control or sterndriveunit shift cable.

Replace cables and adjust.

Shift cable too short (sharp bends) ortoo long (loops and long bends).

Select and install proper length cable.

Corroded shift cables. Replace, adjust and check for waterleakage.

Internal wear in remote control box. Repair as needed.

Shift cable attaching nuts too tight (endcannot pivot).

Properly install nuts.

Shift cable pivot ends are corroded ornot lubricated.

Clean and lubricate.

Sterndrive Unit In Gear, Will Not Shift Out Of GearNOTE: For additional information on troubleshooting, refer to Section 2A -Troubleshooting Shift Problems.


Shift cable broken. Replace cable and adjust.

Cable end not connected in sterndriveunit.

Remove and reinstall sterndrive unit.

Remote control damaged. Repair or replace remote control.

Internal shift mechanism damage. Repair or replace as necessary.


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Gear Housing Noise


Metal particles in sterndrive unitlubricant.

Disassemble, clean and inspect andreplace necessary components. (Referto Section 3B, 3C, or 3D)

Propeller incorrectly installed. Inspect mounting hardware. Installpropeller correctly.

Propeller with untrue or out-of-balanceblades.

Repair or replace, as required.

Propeller shaft bent. Inspect and replace if necessary. (Referto Section 3B, 3C, or 3D)

Incorrect gear shimming.Check gear housing backlash and piniongear height. (Refer to Section 3B, 3C,or 3D)

Worn or damaged gears and/or bearingscaused by impact, overheating orimproper shimming.

Disassemble, inspect and replace.(Refer to Section 3B, 3C, or 3D)

Drive Shaft Housing Noise


Engine flywheel housing contactinginner transom plate or exhaust pipe.

Determine cause for interference (looseengine mounts, transom too thin, etc.)and correct as necessary.

Abnormal sterndrive operation. Instruct operator on proper operatingtechnique.

U-joint cross and bearing assemblyretaining rings improperly installed or ofincorrect size.

Ensure that proper thickness retainingrings are used and that rings are fullyseated in U-joint bearing cap grooves.(Refer to Section 3A)

Excessive side-to-side play in U-jointcross and bearing assemblies.

Replace cross and bearing assembly.

U-joint bearing caps contacting U-jointbellows retention sleeve.

Ensure that proper cross and bearingassemblies are used. If interference issevere, replace cross and bearingassembly and / or sleeve assembly.

U-joint cross and bearings rough.Replace assemblies. Signs of scoring,galling, or roughness are the result oflack of lubricant. (Refer to Section 3A)

O-rings missing or flattened out onU-joint shaft causing shaft to rattleagainst ID of gimbal bearing.

Install new O-rings. (Refer to Section3A)


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Drive Shaft Housing Noise (continued)


Worn U-joint shaft splines and/or enginecoupler splines.

Remove U-joint coupling end yoke andinsert into gimbal bearing and enginecoupling. Rotate shaft back and forth. Ifplay is excessive, replace U-joint couplingend yoke and/or engine coupler, asnecessary.

Engine alignment incorrect or enginecoupler crooked.

Adjust alignment. Ensure that alignmenttool moves in and out of coupler freely.After proper alignment has been obtained,check for a crooked coupler by rotatingengine coupler 1/2 turn and recheckingalignment. If proper alignment is no longerobserved, coupler is crooked and must bereplaced. (Refer to Section 2)

Gimbal bearing rough.

Replace gimbal bearing. (Refer to Section4)

IMPORTANT: Gimbal bearing and carrierMUST BE replaced as an assemblybecause they are a matched set. Failureto do this may result in a loose bearing fitin carrier.

Loose gimbal bearing.

Reinstall bearing assembly using a newtolerance ring if carrier is loose in gimbalhousing. If bearing is loose in carrier,bearing assembly must be replaced.(Refer to Section 4)

Gimbal bearing not fully seated in gimbalhousing.

Sterndrive bearing assembly into place.

Excessive clearance between gimbal ringand gimbal housing. This could causemisalignment between bell housing andgimbal housing and also may allow gimbalring to vibrate up and down.

Check and adjust clearance. (Refer toSection 4)

Improperly installed or failed rear enginemounts. This will affect engine alignment,but usually is not detectable with enginealignment tool.

Check for uneven mount height, or looseor soft mounts. Make sure there isclearance between flywheel housing andfiber washer. If no clearance exists,mounts have probably sagged. Installmounts correctly or replace, as necessary.


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Drive Shaft Housing Noise (continued)


Boat transom too thin. Thickness: 51mm (2 in.) minimum, 57 mm (2-1/4 in.)maximum.

Add thickness to transom.

Boat transom thickness uneven. Thiscould affect engine to transom assemblyalignment and is usually not detectablewith alignment tool. Variation: 3 mm(1/8 in.) maximum.

Repair boat as necessary.

Bell housing contacting gimbal ring. Thiswould cause knocking in the fullytrimmed IN position only.

Check for soft or split trim cylinderbushings and loose or worn hinge pinbushings. (Refer to Section 5B)

Stringer height uneven or transomassembly installed angled on boattransom. This will affect enginealignment, but is usually not detectablewith alignment tool.

Measure the distance between theengine flywheel housing and the innertransom plate on both sides. If distancesare uneven, the problem may be due touneven stringer height or a cockedtransom assembly. Adjust the stringerheight or relocate the transom cutout asrequired.

Weak boat transom or boat bottom thatflexes under power and causes enginemisalignment - this condition will usuallycause engine coupler failure.

This condition can sometimes bedetected by having someone apply forceto the top of the sterndrive unit whilewatching the inner transom plate. Ifmovement can be observed, thetransom is weak and must be repaired.

Rear engine mount attaching hardwareimproperly installed or missing.

Reinstall hardware correctly.

Engine mounting holes drilled off-centerin inner transom plate engine supportsor engine flywheel housing

Ensure that the holes are equallyspaced fore and aft and are equaldistance from the centerline.

Misalignment between bell housing,gimbal housing and engine coupler.

Contact your service center and arrangeto have a technical servicerepresentative check the unit using aspecial gauge.


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Power Shift

System Does Not React


Vacuum leaks.

With engine running, check for vacuumleaks. Squirt oil on fitting and hoseconnections and on the shiftcylinder-to-end plate joint. If oil is suckedin at any point, a vacuum leak exists.Repair leak.

Improper installation. Reinstall.

System Binds


Remote control.

Disconnect input cable at power shiftcylinder. Disconnect throttle cable atcarburetor or injector pump. Operateremote control. If binding occurs, findcause of binding in either cable orremote control and correct binding. If nobinding occurs, check vacuum.

Slow or no shift.Check vacuum drop-off. If vacuum dropsoff to “0” psi in less than 5 seconds,install repair kit.

Cable movement.

Check movement of cable from shiftplate to sterndrive unit including shiftinglinkage movement in sterndrive unit forbinding. Replace or adjust shift cablefollowing procedures in Section 2A.


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Performance Troubleshooting

Low WOT Engine RPM


Improper sterndrive unit trim angle. Properly adjust sterndrive unit trimangle.

Damaged propeller. Repair or replace.

Improper propeller pitch. Water test boat using a lower pitchpropeller.

Dirty or damaged boat bottom. Clean and/or resurface boat bottom.

Sterndrive installation too low ontransom.

Contact boat manufacturer forinstallation specifications.

Permanent hook in boat bottom (someboats are built with a slight hook forcorrect boat performance).

Check for a hook in the boat bottom byplacing a straight edge, at least 2 m (6ft) long, under the bottom edge of thetransom. If a hook is found, contact theboat manufacturer.

Power hook or weak boat bottom.

Water test boat. Boat will performnormally until hook develops at highspeed, then loss of rpm and speed willoccur. Contact boat manufacturer.

High WOT Engine RPM


Propeller ventilating. Determine cause for ventilation.

Improper propeller pitch. Water test boat using a higher pitchpropeller.

Propeller hub slipping. Replace hub or replace propeller.

Sterndrive installation too high ontransom.

Contact boat manufacturer forinstallation specifications.

Engine coupler hub spun. Replace coupler.

Propeller Ventilating/Cavitating


Sterndrive unit trimmed too high. Trim sterndrive unit IN/DOWN.

Incorrect propeller. Install correct propeller.


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Poor Boat Performance And/Or Poor Maneuverability - Bow Too Low



Boat is bow heavy.

Redistribute boat load to stern. If bowoverweight is caused by permanentlyinstalled fuel tanks, contact the boatmanufacturer.

Boat is underpowered. Check horsepower to weight ratio.Contact the boat manufacturer.

Permanent hook in boat bottom (someboats are built with a slight hook forcorrect boat performance).

Check for a hook in the boat bottom byplacing a straight edge, at least 2 m (6ft) long, under the bottom edge of thetransom. If a hook is found, contact theboat manufacturer.



Poor Boat Performance And/Or Poor Maneuverability - Bow Too High



Boat is stern heavy.

Redistribute boat load to bow. If sternoverweight is caused by permanentlyinstalled fuel tanks, contact the boatmanufacturer.

Propeller pitch too high. Water test the boat using a lower pitchpropeller.

Permanent rocker in boat bottom (someboats are built with a slight rocker forcorrect boat performance).

Check for a rocker in the boat bottom byplacing a straight edge, at least 2 m (6ft) long, under bottom edge of thetransom. If a rocker is found, contact theboat manufacturer.




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Power Steering

Hard Steering - Helm And Cable


Damaged steering cable. Replace cable. (Refer to Section 2)

Steering cable too short (sharp bends)or too long (loops and long bends).

Select and install proper length cable.(Refer to Section 2A)

Steering cable corroded or notlubricated.

Lubricate or replace the cable.

Over-lubed cable. Replace cable.

RideGuide rack or rotary head notlubricated.

Disassemble and lubricate.

Hard Steering (Engine Running) - Power Steering System


Low power steering pump fluid level. Check fluid level. (Refer to Section 6A)

Loose power steering pump sterndrivebelt.

Adjust belt tension. (Refer to Section6A)

Air in system. Cycle to remove air. (Refer to Section6A)

Fluid leak. Locate and correct source of leak.(Refer to Section 6A)

If the above 4 steps do not solve theproblem, test the power steering system.

Test power steering system. (Refer toSection 6A)

Power Steering System External Fluid Leaks


Pump reservoir leaking at fill cap(reservoir too full).

Remove fluid to bring to proper level.

Pump reservoir leaking at fill cap (air orwater in fluid).

Locate source of air or water andcorrect. Air may enter because of lowreservoir fluid level or internal pumpleak. Test pump. (Refer to Section 6A)

Loose hose connections. Tighten hose connections.

Damaged hose. Replace hose.

Bad cylinder piston rod seal. Replace cylinder.

Damaged or worn control valve seals. Replace cylinder.

Bad power steering pump seals andO-rings.

Repair pump. (Refer to Section 6A)

Cracked or porous metal parts. Replace parts.


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Compact Hydraulic Steering

Important InformationWhenever a troubleshooting solution calls for removal from vessel and/or dismantling ofsteering system components, such work must be carried out by a qualified marinemechanic. The following is offered as a guide only and neither Mercury MerCruiser nor thehelm manufacturer are responsible for any consequences resulting from incorrect repairs.

Most faults occur when the installation instructions are not followed and usually show upimmediately upon filling the system. The most common faults encountered and their likelycause and solution are provided in the following.

Sometimes when returning the steering wheel from a locked position, a slight resistancemay be felt and a clicking noise may be heard. This should not be mistaken as a fault, asit is a completely normal situation caused by the releasing of the lock spool in the system.

WARNINGAvoid serious injury or death due to FIRE or EXPLOSION. Ensure that enginecompartment is well-ventilated and that no gasoline vapors are present to preventthe possibility of a FIRE or EXPLOSION.

Helm Becomes Jammed During Filling


Blockage in the line between the helmsand the cylinders.

Ensure that hoses were not kinked orpinched during installation. If so, thehose must be removed and replaced.

System Difficult To Fill


Air in system. Review filling instructions.

Steering Hard To Turn


Steering cylinder pivot bushings are tootight or trunion is bent, causingmechanical binding.

To test, disconnect clevis from steeringlever and turn the steering wheel. If itnow turns easy, correct cause ofmechanical binding. Please note thatexcessively loose connections tosteering cylinder or steering lever canalso cause mechanical binding.

Restrictions in hoses. Find restrictions and correct.

Air in hydraulic fluid. Refer to filling and purging instructions.

Wrong hydraulic fluid has been used tofill steering system.

Drain system and fill with approvedhydraulic fluid.


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Helm Unit Bumpy - Requires Too Many Turns


Dirt in inlet check of helm pump. Replace helm unit.

Power Trim Electrical System

NOTE: The numbers in quotation marks, e.g. “3“, refer to the Power Trim System WiringDiagram.

Power Trim Pump Motor Will Not Operate In The OUT/UP Or IN/DOWNDirection - Solenoids Do Not Click


Bad electrical connection at the 110 ampfuse or the battery, or the harness cameunplugged from the pump

Check all electrical connection points.

20 amp fuse blown.

Determine cause for the blown fuse andcorrect. Then replace fuse.

NOTE: If fuse blows while trimmingOUT/UP or raising sterndrive unit, prob-lem may be due to grounded trim limitswitch leads. To check for groundedcondition, disconnect trim limit switchleads at bullet connector ”14,” ”15,” ”16,”and ”17.” If sterndrive unit can now beraised (using Trailer switch), trim limitswitch or leads are grounded.

Power trim pump battery cables orwiring harness connections corroded orloose.

Clean and/or tighten connections ”1,””2,” ”4,” ”10,” ”11,” ”12” and ”18” asnecessary.

Trim control wiring harness connectorloose or corroded.

Clean and secure connection ”13” asnecessary.

110 amp fuse blown (does not apply tointermittent problem).

Check for voltage at terminal ”4.” If novoltage indicated, determine cause ofblown fuse.

Open circuit in trim control wiringharness.

Check for battery voltage at terminal ”8”while trimming OUT/UP and at terminal”6” while trimming OUT/UP. If no voltageis indicated, check trim control for aloose or corroded connection or adamaged power supply lead in harness.

Thermal circuit breaker in pump motoropen.

Replace commutator end plateassembly.


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Power Trim Pump Motor Will Not Operate In The OUT/UP Or IN/DOWNDirection - Both Solenoids Click


Faulty solenoids or loose or corrodedconnections.

Check for battery voltage at terminals“5” while trimming OUT/UP. If no voltageis indicated, check connections “2,” “3,”“4” and “5” and/or replace solenoids.

Pump motor brushes stuck, corroded orworn out.

Clean or replace as required.

Armature commutator dirty. Clean or replace armature as required.

Armature faulty. Test for shorted, open or groundedcondition and replace if needed.

Field and frame faulty.Check for open or grounded condition.Replace field and frame assembly ifneeded.

Water or oil in motor. Replace motor assembly.

Pump gears frozen. Replace pump valve body and gearassembly.

Power trim pump harness or trim controlharness shorted between OUT/UP andIN/DOWN circuit (pump trying to operatein OUT/UP and IN/DOWN directionsimultaneously).

Disconnect BLU/WHI lead from solenoidterminal “8.” If pump motor will nowoperate in the OUT/UP direction, a shortin the harness exists. Repair or replaceharness as needed.

Power Trim Pump Motor Operates In The OUT/UP Direction, But Not In TheIN/DOWN Direction - IN/DOWN Solenoid Does Not Click


Loose or dirty solenoid connections. Check connections “6” and “7” and cleanand/or tighten as required.

Open IN/DOWN circuit in trim control orpump wiring harness.

Check for battery voltage at terminal “6”while trimming OUT/UP. If no voltage isindicated, check for a loose or corrodedOUT/UP circuit connection, damagedOUT/UP circuit lead or a faulty OUT/UPtrim switch. Repair or replace asrequired.

Solenoid faulty. Replace solenoid.


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Power Trim Pump Motor Operates In The OUT/UP Direction, But Not In TheIN/DOWN Direction - IN/DOWN Solenoid Clicks


Loose or dirty solenoid connections. Check connections “4” and “5.” Cleanand/or tighten as necessary.

Faulty solenoid.Check for battery voltage at terminal “5”while trimming IN/DOWN. If no voltageis indicated, replace solenoid.

Faulty IN/DOWN field winding. Replace field and frame assembly.

Power Trim Pump Motor Operates In The IN/DOWN Direction, But Not In TheOUT/UP Direction - Both Trim And Trailer Switches Inoperative - OUT/UPSolenoid Does Not Click



Open OUT/UP circuit trim control orpump wiring harness.

Check for battery voltage at terminal “8”while trimming OUT/UP. If no voltage isindicated, check for a loose or corrodedOUT/UP circuit connection, blown fuse (iftrim control is equipped), damagedOUT/UP circuit lead or a faulty OUT/UPtrim switch. Repair or replace asnecessary.

Faulty solenoid. Replace solenoid.

Power Trim Pump Motor Operates In The IN/DOWN Direction, But Not In TheOUT/UP Direction - Both Trim And Trailer Switches Inoperative - OUT/UPSolenoid Clicks



Faulty solenoid.Check for battery voltage at terminal “3”while trimming OUT/UP. If no voltage isindicated, replace solenoid.

Faulty OUT/UP field winding. Replace solenoid.


Page 1C-16 90-863160--1 JUNE 2003

Trim Control OUT/UP Trim Switch Inoperative - Trailer Switch Operates


Trim limit switch lead bullet connectorsloose or corroded.

Clean and/or tighten connections “14,”“15,” “16” and “17” as necessary.

Faulty trim limit switch or leads.

Disconnect trim limit switch leads fromtrim harness. Connect a continuity meterbetween leads “16” and “17.” Continuityshould be indicated with sterndrive unitin full IN/DOWN position. If not, checkfor damaged leads or poor connections.If this is not the cause, replace trim limitswitch.

Open trim control OUT/UP circuit.

Check for a loose or corroded OUT/UPcircuit connection, damaged OUT/UPcircuit lead or faulty OUT/UP trim switch.Repair or replace as necessary.

Trim Control Trailer Switch Inoperative - Trim OUT/UP Switch Functions


Open trim control trailer circuit.Check for a faulty trailer switch, loose orcorroded connections or damaged trailercircuit lead.

Trim System Functions While Unattended


Faulty trim or trailer switch. Replace switch.

Shorted trim pump harness or trimcontrol harness.

Repair or replace as required.


90-863160--1 JUNE 2003 Page 1C-17

Power Trim System Wiring Diagram

BLK = BLACKBLU = BLUEBRN = BROWNGRY = GRAYGRN = GREENORN = ORANGEPNK = PINKPUR = PURPLERED = REDTAN = TAN

WHT = WHITEYEL = YELLOWLIT = LIGHT

DRK = DARK

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NOTE: Numbered callouts refer to connections referenced in the Power Trim ElectricalSystem troubleshooting charts.

a - 20 amp. fuseb - Ground bolt (floor mount)c - UP solenoidd - 110 amp. fusee - DOWN solenoidf - Trim/Trailer switchg - Neutral switch to instrument wiring harnessh - Trim limit switch


Page 1C-18 90-863160--1 JUNE 2003

Power Trim Hydraulic System

NOTE: The numbers in quotation marks, e.g. “3,” refer to the Power Trim HydraulicSchematic.

Sterndrive Unit Cannot Be Trimmed OUT/UP, Trims Slowly Or With JerkyMovements


Power trim pump oil level low. Check for cause of low oil level andcorrect. Add oil and bleed trim system.

Air in trim system.Check for cause of entry and correct.Add oil to pump and bleed air fromsystem.

O-rings damaged on Manual ReleaseValve (if equipped) or valve notcompletely closed.

Replace valve and/or close completely.

Insufficient pump pressure or pumpshuttle valve stuck.

Test. If shuttle 1 is stuck, replace pumpadapter (Refer to Section 5A). Ifpressure is low, replace adapter orattempt to repair by replacing thefollowing components:

� OUT/UP Pressure Relief Valve

� Thermal Relief Valve

Hoses reversed on 1 cylinder only. Connect hoses 7 and 8 correctly.

Trim cylinders binding.Check for cause of binding (bent pistonrod, scored cylinder). Repair or replaceas necessary.

Gimbal housing-to-trim pump hydraulichose pinched.

Replace hose 7.

Up pressure relief valve has dirtparticles under check ball.

Replace with a new valve kit.

Sterndrive Unit Will Not Stay In Trimmed OUT/UP Position


Air in trim system. Check for cause of entry. Fill and bleedsystem.

Shuttle valve (poppet valve). Check for dirt. Install new poppet valve.

Sterndrive Unit Trails OUT/UP On Deceleration Or When Shifting Into Reverse- Unit Thumps When Shifting


Trim pump IN/DOWN circuit leakinginternally.

Test according to appropriate servicemanual. Replace adapter or attempt torepair by replacing the pilot check valvesor seals. (Install Trim Pump Rebuild Kit)


90-863160--1 JUNE 2003 Page 1C-19

Oil Foams Out Of Pump Fill/Vent Screw


Contaminated oil. Flush system with clean oil refill pumpand bleed trim system.

Oil level low.Check for cause of low oil level andcorrect. Add oil to pump and bleedsystem.

Sterndrive Unit Cannot Be Lowered From UP Position Or Lowers With JerkyMovements


Air in trim system. Check for cause of entry. Fill and bleedtrim system.

Low oil level. Add oil.

Insufficient IN/DOWN pressure or shuttlevalve stuck.

Test. If shuttle 1 is stuck, replace pumpadapter. (Refer to Section 5A)

If pressure is low, replace adapter orattempt to repair by replacing thefollowing items:

� IN/DOWN pressure relief valve 1.

Trim cylinders binding. Check for cause of binding. Repair orreplace as necessary.

Gimbal housing-to-trim pump hydraulichose pinched.

Replace IN/DOWN hose 8.

Hoses reversed on 1 trim cylinder only. Reconnect hoses correctly.

Sterndrive unit binding in gimbal ring. Check for cause of binding and replace.

Down pressure relief valve (6) has dirtparticles under check ball.

Replace with a new valve kit.

Sterndrive Unit Will Not Stay In Full UP Position For Extended Periods


External leakage. Check for cause and correct. Add oil to pump and bleed trim system.

Pump OUT/UP circuit leaking internally.

Test. (Refer to Section 5A) Replaceadapter 2 or attempt to repair byreplacing the following:

� Thermal relief valve 4.

� Poppet valves seals 9.

Trim cylinder(s) leaking internally andpump DOWN circuit leaking internally(both must be faulty to cause thisproblem).

Rebuild cylinders 5 Repair or replaceadapter 2 as necessary.


Page 1C-20 90-863160--1 JUNE 2003

Sterndrive Will Not Stay In The Trimmed OUT/UP Position When Underway


Air in trim system. Check for cause of entry. Fill and bleedsystem.

Leaky poppet valve. Install repair kit for poppet valve 1.

Sterndrive Unit Trails OUT/UP On Deceleration Or When Shifting Into Reverse- Unit Thumps When Shifting


Trim cylinders leaking internally. Test. (Refer to Section 5A) Rebuild orreplace cylinders as necessary.

Trim pump IN/DOWN circuit leakinginternally.

Test. (Refer to Section 5A) Replaceadapter or attempt to repair by replacingthe following:

� Pilot check valves or seals 9.

� Install trim pump rebuild kit

Trim Motor Operates But Does Not Pump Oil


Broken coupler between the pump andthe motor.

Replace the coupler.

Plugged pick-up screens. Replace pick-up screens.

Trim Pump Operates Slowly In Both Directions


Check the condition of the oil; it may becontaminated and thick like honey.

Remove the reservoir and clean out thecontaminated oil.

Trim Pump Operates Slowly With A Laboring Sound


A possible tight adapter pump gear orwater or oil in the motor.

Replace the pump assembly in theadapter or replace the electric motorassembly.


90-863160--1 JUNE 2003 Page 1C-21

Power Trim Hydraulic Schematic

73552

�

�

��

�

�

�

�

1 - Shuttle2 - Pump adapter3 - UP/OUT pressure relief valve4 - Thermal relief valve5 - Trim cylinder

6 - IN/DOWN pressure relief valve7 - UP/OUT hose8 - IN/DOWN hose9 - Poppet valves


Page 1C-22 90-863160--1 JUNE 2003

Corrosion Protection

NOTE: The numbers in quotation marks, e.g. “3,” refer to the MerCathode ControllerWiring Diagram.

Corrosion On Underwater Parts, Without MerCathode Or Impressed CurrentProtection


Sacrificial anodes consumed. Replace anodes when 50% consumed.

Stainless steel propeller installed. Add MerCathode (impressed currentprotection) or additional sacrificial anodes.

Sacrificial anodes not grounded tosterndrive.

Remove anodes, clean contact surface,reinstall and check continuity.

Loss of continuity between underwaterparts and ground.

Provide good ground connections.

Shore power causing overload of anode(s)and/or MerCathode.

Disconnect shore power or installQuicksilver isolator.

Paint on sterndrive heavily worn (exposingmore metal).

Prime and repaint and/or install additionalanodes.

Sacrificial anodes painted. Remove paint or replace anodes.

Sterndrive tilted so far that anodes are outof the water.

Leave sterndrive down, install additionalanode (below waterline) or transom mounta MerCathode.

Only power trim cylinders are corroded. Provide good ground to sterndrive. Allparts must be grounded.

Corrosion in area of exhaust outlets.Exhaust deposits can cause corrosion.

Remove deposits with marine or auto wax.

Corrosion occurring after unit removedfrom saltwater.

Wash exterior and flush interior with freshwater.

Corrosion and/or salt build-up betweenmating parts.

Exclude moisture from between matingparts with 2-4-C with Teflon.

Stainless Steel parts corroding:

Tightly wrapped fishing line or foreignmaterial excludes oxygen, causingcorrosion.

Iron particles, such as from a wire brush,cause rusting.

Propeller pitting can occur if electricalcontinuity is lost.

Clean parts, remove foreign material,ensure continuity.


90-863160--1 JUNE 2003 Page 1C-23

Corrosion On Underwater Parts, With MerCathode Or Impressed CurrentProtection - Sterndrive Unit Corroding


Poor connection between referenceelectrode (BRN) lead or anode (ORN)lead and MerCathode controller.

Clean and/or tighten connection. Repairwiring.

Faulty MerCathode reference electrode.

Disconnect reference electrode lead(BRN) from the controller “R” terminal.Connect the lead to positive (+) terminalof a digital multi-meter (set on 0-2000millivolt scale). Connect negative (–)meter lead to negative (–) batteryterminal. Note meter reading; thenrepeat the test with a test silver/silverchloride reference electrode held behindthe sterndrive. The same reading shouldbe obtained in both cases. If not, replacethe reference electrode.

Faulty MerCathode controller.

With anode and reference electrodeleads connected to controller, connect ajumper wire between “R” andnegative(–) terminals on controller.Connect positive (+) lead of volt meter(set on 0-20 scale) to “A” terminal oncontroller. Connect the negative (–)meter lead to the negative (–) controllerterminal. Reading should be as follows:

� Freshwater Areas = 11.5 voltsminimum.

� Seawater Areas = 3.55 volts minimumIf the reading is low, replace thecontroller.

Too much cathode (such as stainlesssteel).

MerCathode system overpowered bylarge quantity of stainless steel belowthe waterline.

Loss of continuity between sterndrivecomponents and ground.

Ensure continuity (check continuity wiresand washers).

Sacrificial anodes consumed, painted orinoperative.

Replace anodes.

MerCathode reference electrode oranode painted.

Remove paint or replace anode orMerCathode reference electrode.


Page 1C-24 90-863160--1 JUNE 2003

Corrosion On Underwater Parts, With MerCathode Or Impressed CurrentProtection - Sterndrive Unit Corroding (continued)


No power to MerCathode controller.

Connect positive (+) lead of volt meter (seton 0-20 volt scale) to positive (+) terminalon the controller and negative (-) voltmeter lead to negative (-) terminal. Metershould indicate battery voltage. Check forblown fuse (if equipped) on a standardMerCathode system. Clean the connectionor repair wiring as required.

Check the fuse in the hot lead.

Check battery.

MerCathode system not functioning Check for loose connections at controllerand battery

Check the grounding wire between thesterndrive and the controller.


90-863160--1 JUNE 2003 Page 1C-25

Corrosion On Underwater Parts, With MerCathode Or Impressed CurrentProtection - Sterndrive Unit Over-protectedSTERNDRIVE OVER-PROTECTED


Faulty MerCathode reference electrode.

Disconnect reference electrode lead(BRN) from “R” terminal on controller.Connect the lead to the positive (+)terminal of a digital multi-meter (set on0-2000 millivolt scale). Connect thenegative (-) meter lead to the negative (-)battery terminal. Note the meter reading;then repeat the test with a test silver/silverchloride reference electrode held behindthe sterndrive. The same reading shouldbe obtained in both cases. If not, replacethe reference electrode.

Faulty MerCathode controller

Check controller output. If the hullpotential indicates overprotection, removethe reference electrode lead from thecontroller. If the controller is off (noimpressed current called for) the voltagebetween the negative (BLK) and theFaulty MerCathode controller. between the negative (BLK) and theanode should be less than 1 volt. Measureamperage; with the reference electrodedisconnected, the amperage between thenegative on the controller and the anodeterminal should be less than 1 milli-amp.Replace the controller if needed.

Stray current corrosion (electrical currentleaves a metal conductor and creates apath through the water).

Disconnect electrical components 1 at atime and observe the multi-meter readinguntil you eliminate the high reading.Correct the source of the stray current.

Poor connection between the MerCathodereference electrode lead (BRN) and the“R” terminal on the controller.

Clean and/or tighten the connection.Repair wiring as needed.

Check the fuse in the hot lead.

Check the battery.

MerCathode system not functioning. Check for loose connections at controllerand battery.

Check the grounding wire between thesterndrive and the controller.


Page 1C-26 90-863160--1 JUNE 2003

Testing Procedure for Corrosion Protection1. Unplug shore power (if equipped).

2. Measure hull potential with silver/silver chloride reference electrode and digital volt/ohmmeter.

3. The following readings indicate the corrosion protection status of the sterndrive unit.

Digital Multi-Meter Corrosion Protection

Freshwater

Between 750 - 1050

millivoltsSterndrive is protected

Below 750 millivolts Sterndrive is corroding

Above 1050 millivolts Sterndrive is overprotected

Digital Multi-Meter Corrosion Protection

Salt, Polluted or MineralLaden Water

Between 850 - 1100

millivoltsSterndrive is protected

Laden WaterBelow 850 millivolts Sterndrive is corroding

Above 1100 millivolts Sterndrive is overprotected

CORROSION SYMPTOMS

• Paint blistering (usually on sharp edges)

• Loosely adhering white corrosion products on exposed aluminum surfaces (do notconfuse these with tenaciously clinging calcium carbonate deposits)

• Aluminum pitting


90-863160--1 JUNE 2003 Page 1C-27

MerCathode Controller

73596

a

b

c

Standard model shown, quick connect similara - Controller (Blue)b - 20 amp. fusec - Electrode

Description Nm lb-in. lb-ft

MerCathode mounting screws 3-4 24-33

The MerCathode controller assembly is located on the back of the front lifting eye.

1. Connect wires to MerCathode controller assembly and MerCathode quick connect.Apply a thin coat of Liquid Neoprene to all connections.

IMPORTANT: Opposite end of RED/PURPLE wire must be connected directly tobattery positive (+) terminal. Do not connect it to a switched positive (+) circuit.MerCathode system must function continuously for proper corrosion protection.

Description Where Used Part Number

A Liquid Neoprene MerCathode connections 92-25711-3


Page 1C-28 90-863160--1 JUNE 2003

NOTES:

Documents

SERVICE MANUAL NUMBER 28 TROUBLESHOOTING IMPORTANT