Mercury Classic 50 compression

[MercNub]

I have a 1987 mercury classic 50 4 cylinder. I took a compression test and got 135 in cylinder 1,2,4 but only 105 in cylinder 3. Is this ok or do I have a problem?

 

[verado7]

Re: Mercury Classic 50 compression

sticky rings maybe but yes thats above the 10% variance between cylinders

 

[MercNub]

Re: Mercury Classic 50 compression

Will running it like this finish killing it or will it just not perform well? Engine rebuild is like $4000.00 from local marine dealer.

 

[JB]

Re: Mercury Classic 50 compression

First, do a decarb, then recheck compression. That will probably even things up.