805164 Mercruiser U BOLT

Engine Diagnosis
If problems are encountered, they should be corrected promptly to maintain an effective, efficient engine. Only qualified personnel should repair and adjust the engine.The serviceman must find the problem and its source, then make the necessary repairs.Not all problems and solutions found in this section will apply to this engine.Refer to the Service Manual for this engine for mechanical problems, the Caterpillar Electronic Locomotive Control System II, SENR3941 for electronic problems or your Caterpillar dealer for more information.1. Engine Will Not Start When Start Switch Is On2. Engine Will Not Start3. Starting Motor Does Not Turn4. Exhaust Temperature Is Too High5. Oil In Cooling System6. Coolant Is Too Hot7. Engine Has Early Wear8. Misfiring Or Running Rough9. Not Enough Power10. Stall At Low RPM11. Sudden Changes In RPM12. Loud Combustion Noise13. Valve Train Noise14. Loud Valve Train Noise15. Too Much Valve Lash16. Little Or No Valve Clearance17. Valve Rotocoil And Spring Lock Are Free18. Noise In Engine19. Too Much Vibration20. Too Much White Or Blue Smoke21. Oil At The Exhaust22. Too Much Lubrication Oil Used23. Too Much Black Or Gray Smoke24. Fuel Consumption Too High25. Low Oil Pressure26. Coolant In Oil 1. Engine Will Not Turn When Start Switch Is On Cause: Battery has low output. Correction: Make reference to Item 3. Cause: Wiring or switches are damaged. Correction: Make reference to Item 3. Cause: Starting motor solenoid is damaged. Correction: Make reference to Item 3. Cause: Starting motor is damaged. Correction: Make reference to Item 3. Cause: Oil pressure switch for prelube pump is damaged. Correction: Make a replacement of damaged switch. Cause: Prelube oil pump is damaged. Correction: Repair or replace pump components as needed. Cause: Inside problem prevents engine crankshaft from turning. Correction: If the crankshaft can not be turned after disconnecting the driven equipment, remove the fuel injectors and check for fluid in the cylinders while turning the crankshaft.If fluid in the cylinders is not the problem, the engine must be disassembled to check for other inside problems. Some of these inside problems are bearing or piston seizure. 2. Engine Will Not Start Cause: Slow cranking speed. Correction: Make reference to Items 3, 4 and 5. Cause: Dirty fuel filter. Correction: Install new fuel fitter. Cause: Dirty or broken fuel lines. Correction: Clean or install new fuel lines as necessary. Cause: Fuel pressure is low. Correction: At starting rpm, the minimum fuel pressure from fuel transfer pump must be 20 kPa (3psi). If fuel pressure is less than 20 kPa (3 psi) change the fuel filter element.Look for air in the fuel system. If fuel pressure is still low, check the fuel control valve and the fuel transfer pump for correct operation. Cause: No fuel to cylinders. Correction: Put fuel in tank. "Prime" (remove the air and/or low quality fuel from the fuel system). Cause: Bad quality fuel. Correction: Remove the fuel from the fuel tank. Install a new fuel filter element. Put a good grade of clean fuel in the fuel tank. Cause: Wrong fuel injection timing. Correction: Make adjustment to timing. Cause: No oil in governor. Correction: After governor repair or replacement add 2 liters (2 quarts) of oil to governor housing. Clean spiral orifice in governor. 3. Starting Motor Does Not Turn Cause: Battery has low output. Correction: Check condition of battery. Charge battery or make replacement as necessary. Cause: Wiring or switch is damaged. Correction: Make repairs or replacements as necessary. Cause: Starting motor solenoid is damaged. Correction: Install a new solenoid. Cause: Starting motor is damaged. Correction: Make repair or replacement of starting motor. 4. Exhaust Temperature Is Too High Cause: Air inlet system has a leak. Correction: Check pressure in the air intake manifold. Look for restrictions at the air cleaner. Correct any leaks. Cause: Exhaust system has a leak. Correction: Find cause of exhaust leak. Make repairs as necessary. Cause: Wrong fuel injection timing. Correction: Make an adjustment to the timing. Cause: Too much load on engine. Correction: Reduce loading. Cause: Not enough air for combustion. Correction: Check air cleaners for restriction. Check mufflers for restriction. Check turbochargers for damage. Cause: Inlet air to engine too hot. Correction: Provide adequate ventilation to engine. 5. Oil In Cooling System Cause: Defect in core of oil cooler. Correction: Install a new core in the oil cooler. Cause: Failure of cylinder head gasket. Correction: Check cylinder liner projection. Replace head gasket. 6. Coolant Is Too Hot Cause: Not enough coolant in system. Correction: Add coolant to cooling system. Check for leaks. Cause: Pressure relief valve has damage. Correction: Check operation of pressure relief valve. Install a new pressure relief valve if necessary. Cause: Combustion gases in coolant. Correction: Find out where gases get into the cooling system. Make repairs as needed. Cause: Water temperature regulators (thermostats) or temperature gauge have damage. Correction: Check water temperature regulators for correct operation. Check temperature gauge operation. Install new parts as necessary. Cause: Water pump has damage. Correction: Make repairs to the water pump as necessary. Cause: Too much load on the system. Correction: Reduce the load. Cause: Wrong fuel injection timing. Correction: Make adjustment to timing. Cause: Reduced sea water flow. Correction: Make repairs to sea water pump as necessary. 7. Engine Has Early Wear Cause: Dirt in lubrication oil. Correction: Remove dirty lubrication oil. Install a new oil filter element. Put clean oil in the engine.Check oil filter bypass valve for a weak or broken spring. Cause: Air inlet leaks. Correction: Inspect all gaskets and connections. Make repairs if leaks are found. Cause: Fuel leakage into lubrication oil. Correction: This will cause high fuel consumption and low engine oil pressure. Make repairs if leaks are found. Install new parts where needed. Make reference to Items 24 and 25. Cause: Too much load on engine. Correction: Reduce loading. 8. Misfiring Or Running Rough Cause: Fuel pressure is low. Correction: Make sure there is fuel in the fuel tank. Look for leaks or bad bends in the fuel line between fuel tank and