Do i need to be concerned about these compression numbers yet

[Tmakaro]

hi, I just did a cold compression test on my 4.3 mercruiser. I couldn’t warm the engine up because my manifolds are currently off. The motor is a 2010 with 560 hours on it.
here are my numbers
1 = 145
3 = 150
5 = 178
2 = 183
4 = 175
6 = 180
seems to idle fine

 

[Mc Tool]

Numbers 1 & 3 dont look so good , and they are next to each other so maybe head gasket leaking between the two.
Has it been sitting for a while ? I would do a hot comp test after you have run it a bit before reading to much into it .

 

[tpenfield]

I usually look for numbers in the 5-10% range of deviation from the 'norm', which in this engine appears to be 175-180 psi. So, yes, #1 & #3, are a bit out of range.

A cylinder leak test would be my next step.

Most engines will idle and even rev-up just fine, despite any issues.

 

[Scott Danforth]

do a leak down test

 

[Tmakaro]

Thanks, I'll try a leak test tonight