JLG X23J - X700AJ Service Manual - Manual (Page 166)

SECTION 3 - CHASSIS & TURNTABLE
3121448 – JLG Lift – 3-139
Normal
Compression
is too high
Compression
is too low
Not restricted
Restricted
Perform the cylinder compression test
. Check the valve clearance and
then perform the cylinder compression test. If
the cylinder compression is too high, remove
carbon deposits in the combustion
chamber.
Check the valve clearance, and
then perform the cylinder compression test.
If the cylinder compression is too low,
perform a leak down test.
If there is no air leakage in the engine, check
the following.
- Valve spring free length
- Valve seat width
- Valve face irregularly worn
- Decompressor operation
- Piston ring side clearance
- Piston ring width
- Piston ring end gap
- Piston skirt O.D.
- Cylinder sleeve I.D.
Check for a restricted spark arrester
(applicable types).
Restart the engine according to the starting
procedure.
Clean the spark arrester.