xr4 150 compression

[hl]

Working on a 1988 150. The compression when the motor is cold is 120 to 119 when the engine is cold. After warning the engine the compression drops to 110 to 100. Which is the most accurate?

 

[JB]

Re: xr4 150 compression

It really doesn't matter, hl. There are too many variables (as you have demonstrated). What does matter is the spread of measurements among the cylinders, all taken by identical procedure under identical conditions. A 10% span is excellent, a 15% span is acceptable.

 

[hl]

Re: xr4 150 compression

Thanks, Won,t worry about the compression