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Troubleshooting

1. Be careful when changing fuel system compo nents gasoline is extremely flammable and high ly explosive under certain conditions Be sure that ignition key is OFF DO NOT smoke or allow sources of spark or flame in the area while chang ing fuel filter Wipe up any spilled fuel immediate ly Avoid gasoline fire or explosion Improper instal lation of brass fittings or plugs into fuel pump or fuel filter base can crack casting and or cause a fuel leak Follow specific procedure given in Section 5A of this manual for all fuel line connec tions Make sure no fuel leaks exist before closing en gine hatch A CAUTION DO NOT operate engine without cooling water being supplied to water pickup holes in gear housing or water pump impeller will be damaged and subsequent overheating damage may result Index 90 823226 1 996 CAUTION DO NOT operate engine without water being supplied to seawater pickup pump on engine or pump impeller may be damaged and subsequent overheating damage to engine may result En gine may be operated with boat out of water if in structions under Running Engine with Boat Out of Water following are completed When running engine with boat out of water be certain that area in vicinity of propeller is clear and that no person is standing nearby As a pre cautionary measure it is recommended that the propeller be removed CAUTION DO NOT run engine above 1500 RPM as suction c
2. Cracked or dirty distributor cap Faulty ignition components Engine synchronizer if equipped hooked up series on purple ignition wire dual engines only shai Index E TROUBLESHOOTING 1C 7 90 823226 1 996 Testing Thunderbolt IV System Be sure that engine compartment is well venti lated and that there are no gasoline vapors pres ent during the following test to prevent a poten tial fire hazard Check all Terminal Connections at Distributor Ignition Module Replace Ignition Module Replace Ignition Module Harness Unplug WHT RED bullet con nector from Dist Term then Check for Voltage on This Lead Replace Ignition Sensor in Distributor Index 1C 8 TROUBLESHOOTING and Ignition Coil Battery OK Distributor Clamping Screw Tight With Key in RUN Position Check for 12 Volts at Positive Terminal on Ignition Coil Check for 1 12 Volts at WHT 0 Volts RED Terminal on Distributor Remove High Tension Lead from Distributor to Coil Insert a Spark Gap Tester from Coil Tower to Ground Remove WHT GRN Lead from Distribu tor Terminal Ignition Key in RUN Position Strike the Termi nal on the WHT GRN Lead against Ground No Spark at Coil Substitute a New Ignition Coil Repeat Above Test No Spark at Coil Replace Ignition Module Spark at Coil IMPORTANT Use a voltmeter when mak ing these tests DO NOT use a test light ALPHA DRIVES ONLY
3. Engine Noise Important Information No definite rule or test will positively determine source of engine noise therefore use the following information only as a general guide to engine noise diagnosis 1 Use a timing light to determine if noise is timed with engine speed or one half engine speed Noises timed with engine speed are related to crankshaft rods pistons piston pins and fly wheel Noises timed to one half engine speed are valve train related The use of a stethoscope can aid in locating a noise source however because noise will travel to other metal parts not involved in the problem caution must be exercised If you believe noise is confined to one particular cylinder ground spark plug leads one at a time If noise lessens noticeably or disappears It is iso lated to that particular cylinder Try to isolate the noise to location in engine front to back top to bottom This can help determine which components are at fault Sometimes noises can be caused by moving parts coming in contact with other components Examples are flywheel or coupler exhaust flap pers rattling against exhaust pipe crankshaft striking pan pan baffle or dipstick tube rocker arm striking valve cover and loose flywheel cov er In many cases if this is found to be the prob lem a complete engine teardown is not neces Sary When noise is isolated to a certain area and com ponent removal and inspection will be required
4. Refer to proper sections of service manual for in formation required for service If noise cannot be distinguished between engine and drive unit remove drive from boat Run a wa ter supply directly to engine Run engine without the drive to determine if noise is still there Valve Cover Area Valve cover area timed to one half engine speed noise could be confined to one cylinder or may be found in any multitude of cylinders Cylinder Area Possible Causes A Sticking valve B Carbon build up C Connecting rod installed wrong Cylinder area may be confined to one cylinder D Bent connecting rod or found in more than one cylinder timed to engine speed E Piston F Piston rings G Piston pin H Cylinder worn Pie Index a 6 1 996 10 20 TROUBLESHOOTING 90 82322 Camshaft Area A Crankshaft timing sprocket B Timing chain Camshaft area front of engine timed to one half C Fuel Pump engine speed D Valve Lifter E Cam Bearings A Fuel Pump Camshaft area center of engine timed to one half B Valve Lifter engine speed C Cam bearing Camshaft area rear of engine timed to one half A Distributor gear engine speed B Valve lifter C Cam bearings A Loss of oil pressure Camshaft area throughout engine timed to one B Valve lifters half engine speed C Cam bearings Crankshaft Area A Crankshaft timing sprocket Crankshaft area front of engine timed to B Timing chain engine spe
5. Unplug shift interrupter switch WHITE GREEN bullet connector from Distributor Ter minal Remove Tachometer GRAY lead only from coil terminal Ret est to isolate these components Check Engine and Instrument Wiring Harness Battery Cables Key Switch Replace Ignition Sensor in Distributor Install New Spark at Coll Ignition Coil 90 823226 1 996 Testing Thunderbolt V Ignition System Check to ensure that tachometer GRY lead is not shorted to ground at the tachometer or within the harness Check all Terminal Connections at Distributor Ignition Module and Ignition Coil Battery OK Distributor Clamping Screw Tight Check Engine With Key in RUN Position and Instrument Check for 12 Volts at Positive Wiring Harness Terminal on Ignition Coil Volts Battery Cables Key Switch Unplug WHT RED bullet connector from Distributor 0 Check for 12 volts on lead coming from module Reconnect WHT RED bullet connectors Remove High Tension Lead from Distributor to Coil Insert a Spark Gap Tester from Coil Tower to Ground Disconnect Replace Ignition WHT GRN Lead from Distribu Sensor in tor Place Ignition Key in RUN at Coll Position Rapidly strike the Ter minal of the WHT GRN Lead that comes from module against Ground See IMPORTANT below Distributor No No Spark at Coill at Coil Substitute a New Ignition Spark Install New Coi
6. Poo fuel high idle RPM timing set too high Rain water running into flame arrestor Hatch cover se Improper combustion causes moisture in the air Spark plug misfiring to accumulate in the cylinder Backwash through the exhaust system Improper engine or exhaust hose installation Cracked exhaust manifold Improper manifold to elbow gasket installation Loose cylinder head bolts Blown cylinder head gasket Check for warped cylinder head or cylinder block Cracked valve seat Porous or cracked casting a a heads cylinder block and intake Index 90 823226 1 996 shai TROUBLESHOOTING 10 27 Engine Overheats Mechanical Engine RPM below specifications at wide Damaged or wrong propeller growth on boat open throttle engine laboring bottom false bottom full of water Wrong ignition timing Timing too far advanced or retarded Sticking distributor advance weights Spark plug wires crossed wrong firing order Lean fuel mixture Refer to Carburetor Malfunctions in this section Wrong heat range spark plugs Exhaust restriction Valve timing off Jumped timing chain or improperly installed A blown head gasket s normally cannot be detected by a compression check Normally the engine will run at normal temperature at low RPM but will overheat at soeeds above 3000 RPM Blown head gasket s Engines that are seawater cooled Using a clear plastic hose look for air bubbles between seawater pump and engine If there
7. range is being used Also check for over advanced ignition timing cooling system malfunction lean fuel air mixtures leaking intake manifold or sticking valves Replace Spark plugs 72421 High Speed Glazing Insulator has yellowish varnish like color indicating that temperatures suddenly have risen usually dur ing hard fast acceleration under heavy load Normal deposits do not get a chance to blow off Instead they melt and form a conductive coating Replace plugs If condition recurs use colder heat range plug and service plugs more frequently 72421 Index 90 823226 1 996 Scavenger Deposits Powdery white or yellow deposits are built up on shell insulator and electrodes This is normal ap pearance with certain branded fuels Accumulation on ground electrodes and shell areas may be unusu ally heavy but may be easily chipped off Plugs can be serviced clean file and re gap and reinstalled 12422 Pre Ignition Damage Pre ignition damage is caused by excessive high temperatures Center electrode melts first followed by ground electrode Normally insulators are white but may be dirty if plug has been misfiring Check for correct plug heat range advanced ignition timing lean fuel mixture incorrect fuel used malfunctioning cooling system leaking intake manifold or lack of lu brication 12422 Uy ol TROUBLESHOOTING 1C 3 Reversed Coil Polarity Concave erosion of ground electrode i
8. servicing clean file and re gap this plug can be reinstalled with good results 72420 Chipped Insulator Chipped insulator usually results from careless plug re gapping Under certain conditions severe deto nation also can split insulator firing ends Plug must be replaced 72420 index 1C 2 TROUBLESHOOTING Wet Fouling Oil Deposits Plug becomes shorted by excessive oil entering combustion chamber usually in engine with many hours of operation Worn piston rings cylinder walls valve guides or valve stem seals are causes of oil en tering combustion chamber Only engine repairs will permanently relieve oil wet fouling IMPORTANT New engines or recently over hauled engines may wet foul plugs before normal oil control is achieved with proper break in pro cedures Such fouled plugs may be serviced clean file and re gap and reinstalled 72420 Cold Fouling Dry black deposits indicate rich fuel mixture or weak ignition Clogged flame arrestor flooding carburetor sticky choke or weak ignition components all are probable causes If however only one or two plugs in set are fouled check for sticking valves or bad igni tion leads After correcting cause service clean file and re gap plugs and reinstall 72421 90 823226 1 996 Overheating Insulator is dull white or gray and appears blistered Electrodes are eroded and there is an absence of de posits Check that correct plug heat
9. to drop Change in oil pressure With modern engines and engine oils low oil pressure readings at idle do not necessarily mean there is a problem If valve lifters do not clatter at idle there is a sufficient volume of Low engine oil pressure at idle oil to lubricate all internal moving parts properly The reason for the drop in oil pressure is that engine heat causes an expansion of the internal tolerances in the engine and also the oil will thinout somewhat from heat Low engine oil pressure at idle after running at a high RPM Refer to No 5 and 6 preceding It is not uncommon to see different oil pressure readings between the two engines as long as both engines fall within specifications Boats with dual engines Differences in oil pressure can be attributed to differences in engine tolerances gauges wiring senders etc Boats with dual stations Refer to No 8 preceding Index EE 90 823226 1 996 TROUBLESHOOTING 1C 23 Low Oil Pressure Cause Special Information Verify with an automotive test gauge Refer to Defective oil pressure gauge and or sender Section 4D for instrument testing Oil broken down contains water or gas wrong Thin or diluted oil viscosity engine running too hot or too cold excessive idling in cold water condensation Relief valve stuck open pickup tube restricted Oil pump worn parts in oil pump air leak on suction side of oil pump or pickup oil tube Oi
10. IMPORTANT INFORMATION 1 Moisture on ignition components Distributor cap or spark plug wires arcing Battery electrical connections damaged wiring Ignition switch Shift interrupter switch Alpha One Models Only Shorted tachometer Disconnect tachometer and try again Ignition timing Spark plugs Fouled burned cracked porcelain Spark plug wires Faulty insulation broken wires 2 3 4 5 6 7 8 9 Cracked or dirty distributor cap h Faulty ignition components Check components m_b _ Engine synchronizer if equipped hooked up in Synchronizers must be hooked up directly at coil terminal series on purple ignition wire dual engines only parallel chute TROUBLESHOOTING Index Table of Contents Precautions Used Spark Plug Analysis Spark Plug Analysis Normal Condition Chipped Insulator Wet Fouling Oil Deposits Cold Fouling Overheating High Speed Glazing Scavenger Deposits Pre Ignition Damage Reversed Coil Polarity Splashed Deposits Mechanical Damage Poor Boat Performance and or Poor Maneuverability Improper Full Throttle Engine RPM RPM Too High RPM Too Low Engine Cranks Over But Will Not Start Or Is Hard To Start Important Information Thunderbolt IV and V Ignition No Spark Testing Thunderbolt IV System Testing Thunderbolt V Ignition System Fuel System Rich Fuel System Lean Miscellaneous Engine Will Not Crank Over Starter Inoperative Index Pag
11. OOTING 1C 13 Carburetor Malfunction A Needle and seat B Float adjustment C Saturated float Flooding D Gaskets leaking E Cracked fuel bowl F Fuel percolation G Automatic choke A Idle RPM too low B Idle mixture screws C Idle passages dirty Rough idle D Throttle valves not closing E Engine flooding F Vacuum leak G Throttle body heat passages plugged A Accelerator pump B Leaking gaskets C Automatic choke D Power piston or power valve E Throttle valves Hesitation or acceleration flatness F Throttle body heat passages plugged G Main metering jets H Float adjustment secondary air valve wind up Index EUS 1C 14 TROUBLESHOOTING 90 823226 1 996 Carburetor Malfunction continued A Main metering jets B Leaking gaskets C Float adjustment Engine surges D Saturated float E Power piston or valve F Throttle valves A Power piston or valve B Float adjustment Low top speed or lack of power C Main metering jets D Leaking gaskets A Idle RPM too low B Idle mixture screws C Throttle valves Poor cold engine operation D Automatic choke E Engine flooding A Idle RPM too low B Idle mixture screws C Engine flooding Engine stalls D Automatic choke E Dirt in carburetor F Accelerator pump G Leaking gaskets Hard starting Refer to Engine Starts Hard Index EE 90 823226 1 996 TROUBLESHOOTING 1C 15 Engine Runs Poorly At Idle C
12. are no bubbles present install clear plastic hose between thermostat housing and manifold s f air bubbles are present at a higher RPM itis a good indication there is a blown head gasket Defective oil pump plugged oil passage low oil Insufficient lubrication to moving parts of engine iaval Index ent Le 10 28 TROUBLESHOOTING 90 823226 1 996 Engine Overheats Cooling System IMPORTANT The first step is to verify if the engine is actually overheating or the temperature gauge or sender is faulty Loose or broken drive belt Seawater shutoff valve partially or fully closed if equipped Loose hose connections between seawater pickup and seawater pump inlet models with belt driven seawater pump only Obstruction will be in front of seawater pickup causing air bubbles to be forced into cooling system Insufficient seawater pump operation Worn pump impeller Obstruction in cooling system such as casting Refer to water flow diagram for engine type flash sand rust salt etc being serviced IMPORTANT Best way to test gauge or sender is to replace them Pump will suck air Pump may fail to prime or will force air bubbles into cooling system Obstruction on boat bottom causing water turbulence Engine circulating pump defective Also refer to Engine Overheats Mechanical IMPORTANT In addition to previous checks make the following checks if engine is equipped with closed cooling L
13. ause Special Information Clogged flame arrestor Improper idle fuel mixture adjustment Engine floods at idle A Problem in ignition system causing the engine to run rough B Idle mixture screw adjusted incorrectly C Bad needle and seat D Incorrect float level drop E If carburetor 2 bbl only has a solid needle replace with a spring loaded needle Moisture on ignition components Cap or spark plug wires arcing Water in fuel Low grade or stale fuel Incorrect ignition timing Automatic choke Spark plugs Fouled burned cracked porcelain Spark plug wires Insulation breakdown wires broken Defective coil Cracked or dirty distributor cap Incorrect float level Dirty carburetor Vacuum leak Leak at manifold or carburetor base Incorrect fuel pump pressure Too low can t supply the carburetor Too high unseats the needle and seat Low compression Also check for blown head gasket Loose or worn distributor Timing changes Water leaking into cylinders Head gasket exhaust manifold cracked head or valve seat Loose or broken engine mounts Index ii 1C 16 TROUBLESHOOTING 90 823226 1 996 Engine Acceleration Is Poor a Memes e Check for stream of raw fuel from accelerator Accelerator pump pump discharge nozzle when opening throttle with engine shut off Vacuum leak Intake manifold or carburetor base Index EE 90 823226 1 996 TROUBLESHOOTING 1C 17 Cause Also ref
14. d there more than likely is a mechanical prob lem Ifthe problem cannot be duplicated the problem is either an operator error or a problem that exists only under certain environmental conditions Water In Crankcase Water in boat bilge Water seeping past piston rings or valves Engine running cold Intake manifold leaking near a water passage Cracked or porous casting Index 1C 26 TROUBLESHOOTING lf water is contained to cylinder s only it is usually entering through the intake system exhaust system or head gasket If the water is contained to crankcase only it is usual ly caused by a cracked or porous block a flooded bilge or condensation lf the water is located in both the cylinder s and the crankcase it is usually caused by water in the cylin ders getting past the rings and valves or complete submersion Checking for rust in the intake manifold or exhaust manifolds is a good idea Rust in these areas will give clues if the water entered these areas Special Information Boat has been submerged or bilge water was high enough to run in through dipstick tube Refer to Water in Engine On Top of Pistons Defective thermostat missing thermostat prolonged idling in cold water Check cylinder head cylinder block and intake manifold Pie 90 823226 1 996 Water On Top Pistons Operator shut engine off at high RPM Engine diesels or tries to run backwards Engine out of rane
15. e 1C 1 10 1 10 2 10 2 10 2 10 3 10 3 10 4 10 4 10 4 10 4 10 5 10 5 10 5 10 6 10 7 10 7 10 7 10 8 10 8 10 8 10 9 1C 10 1C 11 1C 11 1C 11 10 12 Charging System Inoperative Noisy Alternator Instrumentation Malfunction Radio Noise Poor Fuel Efficiency Carburetor Malfunction Carburetor Malfunction continued Engine Runs Poorly At Idle Engine Acceleration Is Poor Engine Runs Poorly At High RPM Troubleshooting With Vacuum Gauge Engine Noise Important Information Valve Cover Area Cylinder Area Camshaft Area Crankshaft Area 0000 c cece aces Miscellaneous Oil Pressure Low Oil Pressure High Oil Pressure Excessive Oil Consumption Water in Engine Important Information Water In Crankcase Water On Top Pistons Engine Overheats Mechanical Engine Overheats Cooling System Insufficient Water Flow From Belt Driven Seawater Pump Power Steering Poor Erratic or No Assist Noisy Pump Fluid Leaks Pie 90 82322 6 1 996 Precautions Always disconnect battery cables from battery BEFORE working on fuel system to prevent fire or explosion Be careful when cleaning flame arrestor and crankcase ventilation hose gasoline is extreme ly flammable and highly explosive under certain conditions Be sure that ignition key is OFF DO NOT smoke or allow sources of spark or open flame in area when cleaning flame arrestor and crankcase ventilation hose
16. ed C Main bearing D Rod bearing A Crankshaft striking pan or pan baffle Crankshaft area center of engine timed to B Main bearing engine speed C Rod bearing A Loose flywheel cover B Loose coupler Crankshaft area rear of engine timed to C Loose flywheel engine speed D Main bearing E Rod bearing A Loss of oil pressure Crankshaft area throughout engine timed to B Main bearings engine speed C Rod bearings Index EE 90 823226 1 996 TROUBLESHOOTING 1C 21 Miscellaneous SS eee Engine spark knock Popping through carburetor Hissing A Vacuum leak Whistle B Dry or tight bearing in an accessory B Dry or tight bearing in an accessory Squeaks or squeals C Parts rubbing together Rattling in exhaust pipe area A Exhaust shutters Index el 1C 22 TROUBLESHOOTING 90 823226 1 996 Oil Pressure Do not rely on the oil pressure gauge in the boat May cause loss of engine RPM oil pressure Oil level in crankcase above FULL mark gauge fluctuation drop in oil pressure and hydraulic valve lifter noise at high RPM Oil level in crankcase below ADD mark Low oil pressure oll pressure gauge fluctuation internal engine noise and or damage This may be a normal condition Oil pressure may read high in the cooler times of the day and when engine is not up to operating temperature As the air temperature warms up and engine is running at normal opening temperature it is normal for oil pressure
17. er to Poor Boat Performance Crankcase overfilled with oil Anti siphon valve if equipped Plugged fuel tank vent Fuel supply Ignition timing Low grade of fuel or water in the fuel Spark plugs Spark plug wires Distributor cap or rotor Coil Distributor Engine overheating Low compression Restricted exhaust Index 10 18 TROUBLESHOOTING Engine Runs Poorly At High RPM Special Information Check oil level with boat at rest in the water Restricting fuel supply Refer to Carburetor Malfunctions See Table of Contents Fouled burned cracked porcelain incorrect heat range Poor insulation broken wires Dirty or cracked Excessive play in shaft Refer to Engine Overheats Worn valves rings cylinders etc ELLE 90 823226 1 996 Troubleshooting With Vacuum Gauge Steady reading between 15 21 inches at idle Normal RPM Extremely low reading but steady at idle RPM Vacuum leak incorrect timing underpowered boat faulty boat bottom Fluctuates between high and low at idle RPM rah lta gasket between two adjacent Fluctuates 4 or 5 inches very slowly at idle RPM Carburetor needs adjustment spark plug gap too narrow valves are sticking Fluctuates rapidly at idle steadies as RPM is aan Valve guides are worn Continuously fluctuates between low and normal reading at regular intervals at idle RPM Stine OV eating vane Index EE 90 823226 1 996 TROUBLESHOOTING 1C 19
18. l Repeat Above Test at Coil Ignition Coil No Spark at Coil Replace Ignition Module IMPORTANT The WHT GRN lead must be touched against ground 2 3 times per second to simulate a running engine Repeat this test several times to ensure that spark is pragex index 90 823226 1 996 TROUBLESHOOTING 1C 9 Fuel System Rich NOTE The following fuel system diagnosis refer primarily to the carbureted engines For additional information pertaining to fuel injection refer to Section 5D of this manual Warm engine carburetor percolation Fuel boils out of float bowl when shut off and warm Floods intake manifold Geacedtanearewor Aaanatechenstenenng Festagesnee e E e e Fuel System Lean Vapor lock Engine will not start after warm engine shut down Automatic choke Stuck open wrong adjustment Miscellaneous Index EUS 1C 10 TROUBLESHOOTING 90 823226 1 996 Engine Will Not Crank Over Starter Inoperative Cause Special Information Remote control lever not in neutral position Battery charge low damaged wiring loose elec trical connections saesawe saree EC Charging System Inoperative e O Refer to Section 4C for complete Charging System diagnosis procedures Index eel 90 823226 1 996 TROUBLESHOOTING 1C 11 Noisy Alternator Loose mounting bolts Drive belt Worn frayed loose Loose drive pulley Worn or dirty bearings Faulty diode trio or stator Instr
19. l passage plugs leaking cracked or porous Oil leak can be internal or external cylinder block Excessive bearing clearance Cam bearings main bearings rod bearings High Oil Pressure Verify with an automotive test gauge rman pa A mA Pie Index a 6 1 996 10 24 TROUBLESHOOTING 90 82322 Excessive Oil Consumption One quart of oil consumed in 5 15 hours of Normal consumption operation at wide open throttle especially in a new or rebuilt engine is normal on bilge floor locate oil leak s eae a C C Glazed scuffed worn stuck improperly Defective piston rings installed ring grooves worn improper break in wrong end gap Out of round scored tapered glazed excessive DEEE VE piston to cylinder clearance cracked piston Index EE 90 823226 1 996 TROUBLESHOOTING 1C 25 Water in Engine Important Information IMPORTANT First determine location of water in engine This information can be of great help when trying to determine where the water came from and how it got into the engine The three most common problems are water on top of pis tons water in crankcase oil water in crankcase oil and on top of pistons The first step after locating water is to remove all the water from the engine by removing all spark plugs and pumping cylinders out by cranking engine over Next change oil and filter Now start engine and see if problem can be duplicated If problem can be dupli cate
20. marine growth D Poor running engine Bow too high SETAT E Improper weight distribution F Rocker in boat bottom G False bottom full of water H Improperly adjusted trim tabs after planes A Drive unit installed too high on transom B Dirty or rough boat bottom C Damaged propeller pitch too small diameter too small D Keel located too close to propeller or too deep in the water E Water pickup or thru hull fittings located too close to propeller F Hook in boat bottom G Propeller plugged up with weeds Propeller ventilating Index el 90 823226 1 996 TROUBLESHOOTING 1C 5 Improper Full Throttle Engine RPM RPM Too High Special information Damaged pitch too low diameter too small Propeller propeller hub slipping Water pickup or thru hull fittings mounted too close to propeller ventilation keel located too Boat close to propeller and or too deep in the water ventilation Drive installed too high on transom wrong gear ratio Unit rimmed out 100 far Engine couple slipping a RPM Too Low Cause Special Information Propeller Damaged pitch too great diameter too great Dirty or damaged bottom permanent or power Boat hook in bottom false bottom full of water Drive installed too low on transom wrong gear ratio Index 1C 6 TROUBLESHOOTING Engine Cranks Over But Will Not Start Or Is Hard To Start Important Information 1 First determine which engine system i
21. ounting tube is loose Leaking valve body or loose fitting spool a Binding in stern drive unit Refer to appropriate Stern Drive Service Manual Index EE 90 823226 1 996 TROUBLESHOOTING 1C 31 Noisy Pump Drive belt Low fluid level Air in fluid Faulty pump Restricted fluid passages Stop nut adjusted improperly Steering cables installed that do not meet BIA standards Fluid Leaks Cause Loose hose connections Damaged hose Oil leaking from top of pump Cylinder piston rod seal Faulty seals in valve Faulty seals in o rings in pump Cracked or porous metal parts Index 1C 32 TROUBLESHOOTING Special Information Check belt tension Air leak in lines pump or air form installation Use stethoscope to listen for noise in pump Kinks or debris in hoses or debris in passages Refer to appropriate Stern Drive Service Manual Refer to appropriate Stern Drive Service Manual Special Information Refer to Section 10A for bleeding instructions System overfilled fluid contains water fluid contains air 90 823226 1 996
22. ow coolant level Antifreeze should be mixed 50 50 or maximum Antifreeze not mixed properly 60 40 60 antifreeze 40 water Heat exchanger cores plugged Water hoses reversed at the water distribution block Refer to water flow diagram in Section 6 Index EE 90 823226 1 996 TROUBLESHOOTING 1C 29 Insufficient Water Flow From Belt Driven Seawater Pump Special Information Seawater shutoff valve partially or fully closed re Clogged or improperly installed sea strainer Loose hose connections between seawater pickup Pump will suck air pump may fail to prime or will and seawater pump inlet force air bubbles into cooling system Seawater pickup plugged Obstruction will be in front of seawater pickup causing air bubbles to be forced into cooling system Obstruction on boat bottom causing water turbu lence Faulty seawater pump ELLE Index a 6 1 996 10 30 TROUBLESHOOTING 90 82322 Power Steering Poor Erratic or No Assist Drive belt Worn broken or out of adjustment Low fluid levei a P Air leak in lines pump or air from installation Leaking hoses Refer to Section 10A for bleeding procedure Cable or helm partially frozen from rust or Steering cables and or steering helm corrosion cable over lubricated improper cable installation Restriction in hydraulic hoses Causes a loss of pressure Control valve not positioned properly not balanced properly or the mounting nut is loose E a m
23. reated by seawater pickup pump may collapse water supply hose and cause engine to overheat Be sure that engine compartment is well venti lated and that no gasoline vapors are present to prevent the possibility of a FIRE or EXPLOSION DO NOT leave helm unattended while performing idle speed adjustment Used Spark Plug Analysis Use the following illustrations for determining ser viceability of spark plug Spark plug condition also can suggest a variety of possible engine malfunc tions and therefore can indicate needed engine re pairs When old plugs are replaced replace entire set Perform plug service only on those plugs suitable for additional service using the following proce dures 1 Remove any oil deposits with solvent and dry plugs thoroughly Open electrode gap wide enough to permit clean ing and filing 3 Remove combustion deposits from firing end of spark plug with a plug cleaner Blow off with com pressed air to remove abrasives 4 File electrode surfaces to restore clean sharp edges Again remove filings with compressed air TROUBLESHOOTING 1C 1 5 Reset gap to specifications by bending only side electrode with proper tool Spark Plug Analysis Normal Condition Few deposits are present and probably will be light tan or gray in color This plug shows that plug heat range is compatible with engine and engine is elec trically and mechanically in good running condition With proper plug
24. s an indication of reversed polarity Center electrode will show only normal wear Engine will misfire and idle rough To correct reverse primary coil leads Replace spark plugs 72422 Splashed Deposits Spotted deposits which sometimes occur after long delayed tune up accumulate after a long period of misfiring When normal combustion temperatures are restored upon installation of new plugs deposits loosen from top of piston and head and are thrown against hot insulator Clean and service plugs and re install 72423 Index 1C 4 TROUBLESHOOTING Mechanical Damage Mechanical damage to spark plug firing end is caused by foreign object in combustion chamber Be cause of valve overlap small objects can travel from one cylinder to another Check all cylinders intake manifold and exhaust material to prevent further damage 72423 IMPORTANT When working on engine spark plug holes and carburetor throat should be kept covered to prevent foreign objects from entering combustion chamber 90 823226 1 996 Poor Boat Performance and or Poor Maneuverability Cause A Improper drive unit trim angle B Improper weight distribution C Boat is underpowered Bow too low D Permanent or power hook in boat bottom E False bottom full of water F Improperly adjusted trim tabs after planes G Dirty boat bottom marine growth A Improper drive unit trim angle B Propeller pitch too great C Dirty boat bottom
25. s causing the problem To make an engine run basic com ponents fuel spark ignition and compression are required If all three components are present the engine should run If any one of the three are missing weak or arriving at the wrong time the engine will not run 3 Check ignition system operation Remove coil wire from tower on distributor cap Hold coil wire near ground and check for spark while cranking engine over Repeat procedure with spark plug wires If there is spark at the spark plug wires re move the spark plugs and make sure they are correct type and heat range and not fouled or burned 2 Determine if there is fuel present by looking down the carburetor venturi while actuating throttle There should be a stream of fuel coming out of the accelerator pump nozzles if the carburetor has fuel 4 Run a compression check on engine to make sure the engine is mechanically sound Thunderbolt IV and V Ignition No Spark Special Information Distributor cap or spark plug wires arcing Cause Moisture on ignition components Battery electrical connections damaged wiring Ignition switch Shift interrupter switch Alpha One Models Only a Disconnect tachometer and try again Shorted tachometer Ignition timing Fouled burned cracked porcelain Faulty insulation broken wires Check components Synchronizers must be hooked up directly coil terminal parallel chute Spark plugs Spark plug wires
26. umentation Malfunction Fay wre ee ercoraeswemings Radio Noise A popping noise that will increase with engine Ignition System wrong spark plugs cracked RPM Noise will stop as soon as engine is distributor cap cracked coil tower leaking spark turned off plug wires moisture on ignition components High pitched whine in the radio Alternator poor brush contact on the slip rings A hissing or crackling noise when instruments Instrumentation loose connections or are jarred with ignition on antennae wire routed too close to instruments Accessories bilge pump bilge blower fish find Varying unexplained noises er depth locator cabin heater motor etc Dis connect one at a time until noise disappears Pie Index a 6 1 996 10 12 TROUBLESHOOTING 90 82322 Poor Fuel Efficiency Prolonged idling slow acceleration failure to cut Operator habits back on throttle once boat is on plane boat over loaded uneven weight distribution Bent damaged or wrong propeller Water test Engine laboring boat for proper operating RPM at wide open throttle Engine compartment sealed too tight Not enough air for engine to run properly Boat bottom Dirty marine growth hook rocker e Idle mixture settings accelerator pump Carburetor adjustments linkage binding choke adjustment carburetor flooding over main fuel jets e E she a Froierunnngteocoserwore el T Index EE 90 823226 1 996 TROUBLESH

Troubleshooting

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