by pumpguy » Sat Aug 27, 2022 11:45 am
What kind of compression tester are you using?
If you're using the kind with a spark plug hole adaptor and hose and the Schrader valve is up at the gauge, you're not getting a true reading because the hose is adding to the combustion chamber volume.
To get a true compression pressure reading, you need to use a tester that has the Schrader valve in the spark plug hole adaptor.
For more info on this subject, Google THE TRUTH ABOUT COMPRESSION TESTING where this is explained in greater detail.