Valve tappets out of adjustment
Valve guides worn out.
See note in
Replace valve guides (par.
Valve seat cracked.
Replace valve seat (par, 177c). See note in paragraph
Cylinder head gasket leaking.
Tighten cylinder head nuts or replace the cylinder head
Cylinder head warped.
Air leak in the intake manifold.
Spark plug gap incorrectly set.
Magneto breaker cam worn out.
Engine Knocks or Pings
Magneto out of adjustment.
Valve timing incorrect
Piston ring broken
Piston pins loose.
Connecting rod bent.
Cylinder bores and pistons worn out.
Rebore cylinders and install oversize pistons (par. 181).
Lack of lubricating oil.
Fill the crankcase with proper grade and quantity of oil.
Refer to LO 5-1185.
Grade of fuel inferior.
Use proper grade of fuel.
Engine Foils to Stop
Combustion chambers overheated.
Inspect coolant level in the radiator. Provide sufficient
Let the engine cool off completely and add coolant (par.
No coolant in the radiator.
Check level. The level must be at the overflow pipe line.
Coolant level low.
Water pump defective.