155 commercial low compression?

[cdoliver]

Hi, I just bought a 1990 omc commercial 155hp. The compression readings are around 78-80 psi all around. Is this low for these motors? It's been sitting for 15 years so I assume it will come up some. The guy I bought it from said they came from the factory with low compression. Will this motor run or is there something I can change like head gaskets to bring the compression up? Thanks

 

[Joe Reeves]

Re: 155 commercial low compression?

Sitting for that length of time, I'd expect it to increase somewhat with running. The compression was decreased to compensate for the poor quality gasoline we're face with.

Normal compression on that engine would be about 95 on the starboard bank and 90 on the port bank.