compression?

[worley1]

1983 mercruiser 485 185 hp 224cid 3.7 closed cooling what is the proper compression for this motor?

 

[The Marine Doctor]

Re: compression?

These were high compression engines...would like to see them around 175 psi.<br /><br />TMD

 

[worley1]

Re: compression?

thanks marine doctor,<br />the compression check the marine done was<br />125,125,105,125 they suspect a blown head gasket<br />I took head off and going to have it magnafluxed and milled all of this started when I had carburater rebuilt put it on and temp guage maxed out heard a sound and steam started bellowing out of exhaust and elbow this boat is very troublesom

 

[beckerdg]

Re: compression?

Head gasket is very common after an overheat on that engine so I am told. Aluminum block and cast iron head expand at different rates and the head gasket ends up the loser. Even readings across all four cylinders is more important than overall reading. According to my manual readings as low a 120 are reasonable.

 

[The Marine Doctor]

Re: compression?

It would seem that your engine has seen a bit of wear.<br /><br />Might be time to clean the whole thing up a bit.<br /><br />Nice to see though that you have found the problem you were looking for. <br /><br />TMD