Compression test procedure?

kucobra

Cadet
Joined
Jul 1, 2007
Messages
18
What is the correct procedure for doing a compression test ?
I see it recommended alot. Engine cold or warm , adding oil to cylinders etc.
Thanks
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Compression test procedure?

Warm engine. Ignition disabled (pull kill switch), remove plugs. Install gauge and spin engine 6 or 8 revs. No oil unless you doing further diagnosis of an apparent issue such as low compression on one cylinder. Numbers should ideally be within 10% of each other and over 100# or whatever your service manual indicates. Throttle needs to be full open on a four stroke motor but it doesn't matter on a two-stroke.
 
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