Johnson 120 Low Compression Right Bank

[Martman]

The boat I am looking at was subject to a good compression test. I did the test. The left bank was 120, right bank was 60, and 75. The owner claims he did that head gasket last year because of a water leak. When I asked him if he torqued them. He indicated he did not. As both right cylinders are low that could indicate a poor head gasket job? I can do the work myself. But should I demand we pull the head off to check for other problems that may have caused the bad compression test. Scored cylinders etc.
Do you replace head bolts on these engines when doing a gasket job?

Thanks

 

[psteurer]

Re: Johnson 120 Low Compression Right Bank

Usually a head gasket blows because of some other problem. Many times that is overheating. So the head gasket is a symptom not a cause for a problem. Personally, I would not buy the motor unless the head was removed and the cylinders inspected. The head bolts should not need to be replaced unless they are damaged.

 

[tashasdaddy]

Re: Johnson 120 Low Compression Right Bank

if he did not torque the head, pull it. could be water in there. it won't take 20 minutes to pull it.

 

[kenmyfam]

Re: Johnson 120 Low Compression Right Bank

Pull head, check inside there. If all is well re-install head, torque it up and re-do the compression check.
Go by the results from there.