21438 Mercury PIN, DOWEL - CRANKCASE TO CYLINDER BLOCK

Troubleshooting
Troubleshooting can be difficult. On the following pages there is a list of possible problems. To make a repair to a problem, make reference to the cause and correction.This list of problems, causes, and corrections, will only give an indication of where a possible problem can be, and what repairs are needed. Normally, more or other repair work is needed beyond the recommendations in the list. Remember that a problem is not normally caused only by one part, but by the relation of one part with other parts. This list can not give all possible problems and corrections. The serviceman must find the problem and its source, then make the necessary repairs.Troubleshooting Index
1. Engine Will Not Turn When Start Switch Is On.2. Engine Will Not Start.3. Misfiring or Running Rough.4. Stall at Low rpm.5. Sudden Changes In Engine rpm.6. Not Enough Power.7. Too Much Vibration.8. Loud Combustion Noise.9. Valve Train Noise (Clicking).10. Oil In Cooling System.11. Mechanical Noise (Knock) In Engine.12. Fuel Consumption Too High.13. Loud Valve Train Noise.14. Too Much Valve Lash.15. Valve Rotocoil or Spring Lock is Free.16. Oil at the Exhaust.17. Little or No Valve Clearance.18. Engine Has Early Wear.19. Coolant In Lubrication Oil.20. Too Much Black or Gray Smoke.21. Too Much White or Blue Smoke.22. Engine Has Low Oil Pressure.23. Engine Uses Too Much Lubrication Oil.24. Engine Coolant Is Too Hot.25. Starting Motor Does Not Turn.26. Alternator Gives No Charge.27. Alternator Charge Rate Is Low or Not Regular.28. Alternator Charge Too High.29. Alternator Has Noise.30. Exhaust Temperature Too High.Engine Crankshaft Will Not Turn When Start Switch Is On Engine Will Not Start Misfiring Or Running Rough Stall At Low RPM Sudden Changes in Engine Speed (rpm) Not Enough Power Too Much Vibration Loud Combustion Noise (Sound) Valve Train Noise (Clicking) Oil In Cooling System Mechanical Noise (Knock) In Engine Fuel Consumption Too High Loud Valve Train Noise Too Much Valve Lash Valve Rotocoil Or Spring Lock Is Free Oil At The Exhaust Little Or No Valve Clearance Engine Has Early Wear Coolant In Lubrication Oil Too Much Black Or Gray Smoke Too Much White Or Blue Smoke Engine Has Low Oil Pressure Engine Uses Too Much Lubrication Oil Engine Coolant Is Too Hot Starting Motor Does Not Turn Alternator Gives No Charge Alternator Charge Rate Is Low Or Not Regular Alternator Charge Too High Alternator Has Noise Exhaust Temperature Is Too High Fuel System
Either too much fuel or not enough fuel for combustion can be the cause of a problem in the fuel system.Many times work is done on the fuel system when the problem is really with some other part of the engine. Finding the source of the problem is difficult, especially when smoke is coming from the exhaust. Smoke coming from the exhaust can be caused by a bad fuel injection valve, but it can also be caused by the following:a. Not enough air for good combustion.b. An overload at high altitude.c. Burning of too much oil.d. Not enough compression.Fuel System Inspection
1. Look at the reading on the gauge for fuel pressure. Not enough fuel pressure is an indication of a problem with the components that send fuel to the engine.2. Check the fuel level in the fuel tank. Look at the cap for the fuel tank to make sure the vent is not filled with dirt.3. Check the fuel lines for fuel leakage. Be sure the fuel supply line does not have a restriction or a bad bend.4. Install a new fuel filter. Clean the primary fuel filter if the machine is so equipped.5. Remove any air that may be in the fuel system.6. Inspect the fuel bypass valve to see that there is no restriction to good operation.Testing Fuel Injection Equipment
An easy check can be made to find the cylinder that is misfiring, or running rough, and causing black smoke to come out of the exhaust pipe.Run the engine at the speed that gives misfiring. Loosen the fuel line nut at a fuel injection pump or valve. This will stop the flow of fuel to that cylinder. Do this for each cylinder until a loosened fuel line is found that makes no difference in engine running. Be sure to tighten each fuel line nut after the test before the next fuel line nut is loosened. Check each cylinder by this method. When a cylinder is found where the loosened fuel line nut does not make a difference in engine running, test the injection pump and injection valve for that cylinder.Checking the Fuel Injection Valves
Check the fuel injection valves for:1. Too much carbon on the tip of the nozzle or in the nozzle orifice.2. Wear of the orifice.3. Nozzle screen being dirty.Use the Caterpillar Diesel Fuel Injection Test Bench to test the nozzle.Checking the Fuel Pump Plunger and Lifter Yoke
Check timing dimension for the fuel injection pumps. Make an adjustment if necessary, with the pump housing off the engine. When an adjustment to the timing dimensions is done correctly, fuel injection in the cylinder will be at the correct time. If the timing dimension is too small, fuel injection will be early. If the timing dimension is too large, fuel injection will be late.When there is too much wear on the pump plunger, the lifter yoke may also be worn and there will not be good contact between the two parts. To stop fast wear on the end of a new plunger, install new lifter yokes in the place of those with wear.
WEAR BETWEEN LIFTER YOKE AND PLUNGER
Fig. A illustrates the contact surfaces of a new pump plunger and a new lifter yoke. In Fig. B the pump plunger and lifter yoke have worn considerably. Fig. C shows how the flat end of a new plunger does not make a good contact with a worn lifter yoke. The result is rapid wear to both parts.An injection pump can have a good fuel flow coming from it but not be a good pump because of slow timing that is caused by wear