Johnson Compression

T

teewhy

Cadet
Joined
Oct 31, 2002
Messages
23
Anybody know what the cylinder compression should be for a 1960 Johnson 40 hp model RD-22? I understand that the engine should be run for a few minutes prior to testing, but, I have not done that. I'm first trying to determine if the engine is worth restoring. So, the test will be a 'dry' one.<br /><br />Thanks very much!
 
rickdb1boat

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: Johnson Compression

teewhy <br /><br />Ideally, you would be looking for at least 100 PSI on all cylinders, with no more than 10 % difference between the cylinders. But being 43 years old, you may have to settle for something less. Also depends on weather it has sat a long time, as the rings may be froze up and not sealing. Put a couple teaspoons of 2 stroke oil in the cylinders and try it. Post your readings and go from there.
 
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