ENGINE TOP END
3-5-41
◆
The following table should be consulted if the obtainable compression reading is not within the
usable range.
Problem Diagnosis Remedy (Action)
Cylinder compres-
sion is higher than
usable range
Carbon accumulation on piston, cylinder
head, and in combustion chamber possibly
due to damaged valve stem oil seal and/
or damaged piston oil rings (This may be
indicated by white exhaust smoke).
Remove the carbon deposits
and replace damaged parts if
necessary.
Incorrect cylinder head gasket thickness. Replace the gasket with a
standard part.
Damaged or missing compression release
cam spring
Replace the spring.
Compression release weights do not move
smoothly.
Replace the compression
release unit.
Cylinder compres-
sion is lower than
usable range
Gas leakage around cylinder head Replace damaged gasket and
check cylinder head warp.
Bad condition of valve seating Repair if necessary.
Incorrect valve clearance. Adjust the valve clearance.
Incorrect piston/cylinder clearance Piston
seizure.
Replace the piston and/or
cylinder
Inspect the cylinder and liner
and replace/repair the cylinder
and/or piston as necessary.
Bad condition of piston ring and/or piston
ring grooves
Replace the piston and/or the
piston rings.
Compression release weights do not move
smoothly
Replace the compression
release unit
Cylinder Compression