So where do you think the compression is being lost?
Rings or head?
From the manual...
• If one cylinder has low compression pressure, pour small amount of engine oil into the spark plug hole
of the cylinder to re-check it for compression.
- If the added engine oil improves the compression, piston rings may be worn out or damaged. Check piston
rings and replace if necessary.
- If the compression pressure remains at low level despite the addition of engine oil, valves may be malfunctioning.
Check valves for damage. Replace valve or valve seat accordingly.
• If two adjacent cylinders have respectively low compression pressure and their compression remains
low even after the addition of engine oil, cylinder head gasket is leaking. In such a case, replace cylinder
head gasket.