Compression

[jrj101]

What would be considered good compression, on a older 70's, 50 hp Mercury 4 cyl. Would 149 each cyl. be adequate? I'm considering buying this motor, and that struck me as high number. Thought I should check with you guys. Thanks for your response.

 

[jrj101]

Re: Compression

The motor is a 1978. What would be considered good compression. I know it varies. Would appreciate any reply. Thanks.

 

[naketa]

Re: Compression

that sounds like its good i know that in a car that is 150hp that comrisson shoud be around 150-175 so that sound good to me how does it run

 

[bubbakat]

Re: Compression

around a hundred is always good for that motor<br />the key to it is to have all cylinders to be within 10 to 15% of each other

 

[jrj101]

Re: Compression

Thanks alot. I plan on buying this motor, and I thought the guy might have pulled that # out of the air.

 

[tmac58star]

Re: Compression

jr,<br />Also check the condition of the spark plug wires and dist. cap, coil, and all wiring up front on either side of the powerhead. I've spent two years replacing these things on a similar vintage Merc 500, but it runs like a stiped *ss ape and very reliable.