37984 Mercury NUT, (.875-14)

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 cannot give all possible problems and corrections. The serviceman must find the problem and its source, then make the necessary repairs.Troubleshooting Index
1. Engine Crankshaft Will Not Turn When Start Switch Is On.2. Engine Will Not Start.3. Misfiring or Running Rough.4. Stalls at Low rpm.5. Sudden Changes In Engine Speed (rpm).6. Not Enough Power.7. Too Much Vibration.8. Load Combustion Noise (Sound).9. Valve Train Noise (Clicking).10. Oil In Cooling System.11. Mechanical Noise (Knock) In Engine.12. Gas Comsumption 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. Exhaust Temperature is Too High.21. Engine Has Low Oil Pressure.22. Engine Uses Too Much Lubrication Oil.23. Engine Coolant Is Too Hot.24. Starter Motor Does Not Turn.25. Alternator Gives No Charge.26. Alternator Charge Rate Is Low or Not Regular.27. Alternator Charge Too High.28. Alternator Has Noise.29. Short Spark Plug Life.30. Pre-Ignition.31. Detonation.32. Gas Supply Line Shutoff Valve Failure.33. Air Starting Motor Turns Slowly or Has a Loss of Power.34. Air Starting Motor Pinion Does Not Engage with the Flywheel.35. Air Starting Motor Runs, Pinion Engages But Does Not Turn Flywheel.36. Air Starting Motor Pinion Does Not Engage Correctly with the Flywheel.37. Electric Protective Systems. See: SENR3202 - ETS TroubleshootingSENR3207 - ETR TroubleshootingSENR3211 - Symbols and Wire Number CodesSENR3467 - System OperationSENR3468 - Wiring SchematicsSENR3469 - Wiring SchematicsEngine Crankshaft Will Not Turn When Start Switch Is On Engine Will Not Start Misfiring Or Running Rough Stalls 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 Gas 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 Exhaust Temperature Is Too High Engine Has Low Oil Pressure Engine Uses Too Much Lubrication Oil Engine Coolant Is Too Hot Starter Motor Does Not Turn Alternator Gives No Charge Alternator Charge Rate Is Low Or Not Regular Alternator Charge Too High Alternator Has Noise Short Spark Plug Life Pre-Ignition Detonation Gas Supply Line Shutoff Valve Failure Air Starting Motor Turns Slowly Or Has A Loss Of Power Air Starting Motor Pinion Does Not Engage With The Flywheel Air Starting Motor Runs, Pinion Engages But Does Not Turn The Flywheel Air Starting Motor Pinion Does Not Engage Correctly With The Flywheel Ignition System
Magneto Installation (Fairbanks Morse)
FLYWHEEL TIMING COVERS
1. Cover over flywheel pointer. 2. Cover over flywheel ring gear.1. Remove cover (1) for timing pointer from the right side of the flywheel housing.2. Remove cover (2) and use a 9S9082 Engine Turning Tool and a 1/2" drive ratchet wrench to turn the flywheel in the direction of normal engine rotation until No. 1 piston is coming up on the compression stroke.
FLYWHEEL TIMING
3. Flywheel pointer. 4. Flywheel timing marks.3. Stop turning when the 18° (BTC) timing mark is directly under the flywheel pointer.4. Make sure magneto drive coupling (6) is turned so the drive slots are at an angle (5) of 13 5° from the horizontal position as shown. If necessary, remove the bolt and pull drive coupling (6) off the drive gear. Turn the coupling to the correct angle and install it back on the drive gear. Install the bolt to hold drive coupling (6) in place.
CYLINDER LOCATION
DRIVE COUPLING POSITION
5. Angle from horizontal position for drive coupling slots. 6. Drive coupling.5. With magneto off the engine, remove timing bolt (7) and turn magneto drive until yellow mark (drilled hole) on pulser gear is in center of opening.
MAGNETO TIMING
7. Timing bolt.6. Install the magneto on the engine. The drive tangs and slots must engage correctly.7. Make final timing adjustment by rotating the magneto at the drive housing mounting and with the use of a timing light when the engine is running at rated speed.Magneto Installation (Altronic)
FLYWHEEL TIMING COVERS
1. Cover over flywheel pointer. 2. Cover over flywheel ring gear.1. Remove cover (1) for timing pointer from right side of engine.2. Remove cover (2), and use a 9S9082 Engine Turning Tool and a 1/2" drive ratchet wrench to turn the flywheel in the direction of normal engine rotation until No. 1 piston is coming up on the compresstion stroke.3. Stop turning when the 25° (BTC) timing mark is directly under the flywheel pointer.
FLYWHEEL TIMING
3. Flywheel pointer. 4. Flywheel timing marks.4. Make sure magneto drive coupling (6)