'69 4hp johnson compression

jackyl

Cadet
Joined
Oct 15, 2010
Messages
7
i have aquired a 69 4hp johnson(4w69b). my question is how much compression should my tester be reading. any help would be appreciated
 

dazk14

Ensign
Joined
Jul 22, 2008
Messages
966
Re: '69 4hp johnson compression

let's start with 80+ and even when it's warm.
 

Rick.

Captain
Joined
Jul 30, 2006
Messages
3,740
Re: '69 4hp johnson compression

Does it run? If it's been sitting for a long time you should get some oil or fuel mix into the cylinders prior to turning it over. Best case would be to run it a bit and then check your compression. I would expect anything from 65 to 95 for numbers. They should be within 10% of one another as well. Mine was in the 70's and went up a lot after a good decarb. Best of luck. Rick.
 
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