Compression Test 1988 15 HP johnson

ace1

Cadet
Joined
Feb 4, 2009
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How much compression should I expect from a rope start engine like this?
 

5150abf

Vice Admiral
Joined
Aug 12, 2007
Messages
5,808
Re: Compression Test 1988 15 HP johnson

100+ is good and all cylinder within 10%.

Check hot if possible but cold is fine to just always check it the same, either hot or cold.

Some motors run 90 no problem, the big point is that all cylinders are close to the same.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Compression Test 1988 15 HP johnson

remove the plugs, pull 5 times, get readings.
 
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