Probable cause
Possible remedy
Adjust valve tappets (par. 136b).
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
gasket (par. 135a).
Cylinder head warped.
Replace cylinder head (par. 135a).
Air leak in the intake manifold.
Replace gasket or manifold (par. 132).
Spark plug gap incorrectly set.
Adjust spark plug gap (par. 117d).
Magneto breaker cam worn out.
Replace magneto breaker cam (par. 190d). See note in
61.
Engine Knocks or Pings
Possible remedy
Probable cause
Adjust magneto (par. 116b).
Magneto out of adjustment.
Remove carbon (par. 135b).
Carbon in the combustion chambers
Adjust valve timing (par. 182c). See note in paragraph
Valve timing incorrect
Piston ring broken
Replace piston ring (par. 178l). See note in paragraph
Piston pins loose.
Replace piston pins (par. 178c). See note In paragraph
Main bearings loose or worn.
Tighten or replace main bearings (par. 180). Bee note
Connecting rod bent.
Replace connecting rod (par. 178). See note in
Connecting rod bearings loose or worn
Tighten or replace connecting rod bearings (par. 178).
See note in paragraph 55.
Cylinder bores and pistons worn out.
Rebore cylinders and install oversize pistons (par. 181).
See note in paragraph 55.
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.
62.
Engine Foils to Stop
Probable cause
Possible remedy
Combustion chambers overheated.
Inspect coolant level in the radiator. Provide sufficient
ventilation.
Remove carbon (par. 135b).
Carbon in the combustion chambers.
63.
Engine Overheats
Possible remedy
Probable cause
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.
Add coolant if necessary (par. 128d).
Replace the water pump (par. 130b).
Water pump defective.
60