Compression test results

"Hi,

I just had a compressi

"Hi,

I just had a compression test done on my inboard 1975 chrysler LM318 225. According to the manual the optimum compression is between 120 and 150 The results on mine are as follows.


Cylinder 1) 120
3) 110
5) 110
7) 110
2) 90
4) 110
6) 90
8) 120

My friend did the test as he is a car mechanic but knows nothing about performance on the water. He said if it were a street engine the compression would be OK but not sure about on a boat. If anyone could respond to this and let me know what they think of my test results it would be greatly apreciated.

Thanks Again"

do a leak down test

do a leak down test

I would say that is acceptable

I would say that is acceptable if your just doing this as a check up but if your looking for a source of a problem a leak down test is probably a good idea. I you put some oil in those cylinders with 90 psi and it hops up you know the loss of comp is in the rings not the valves. Either way 20 pounds difference is not enough to worry me.

will