compression test

LHUDSON

Seaman
Joined
May 31, 2011
Messages
58
What are the steps in performing a compression test on my 4 cylinder volvo inboard.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: compression test

1. Have fully charged battery.
2. Ground coil wire to prevent sparks.
3. Open throttle to WOT (prevents sucking fuel into the cylinder being tested)
4. Remove ALL spark plugs
5. Crank engine to max compession (Don't go crazy waiting on each 1 lb increment, max compression of major gauge movement.)
6. Compression on your 125 should be in the 145 to 175psi range, and within 15% of each other.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: compression test

Wide Open Throttle
 
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