Low compression

hadaveha

Petty Officer 1st Class
Joined
Mar 17, 2009
Messages
389
What's considerd low compression I know you want it to be with in 10 percent between cylinders, but if it is within the 10 percent what is low
 

sojo81007

Seaman Apprentice
Joined
Aug 20, 2011
Messages
35
I think a lot of it has to do with the outboard you have....for instance I run old OMC outboards and good compression is 75-100 PSI whereas newer outboards shoudl be quite a bit higher. 125-130 seems to be a good number from a lot of the posts I read.
 

jakedaawg

Rear Admiral
Joined
Jun 26, 2012
Messages
4,275
It depends, what motor and model number engine are we talking about.

Also, some inexpensive tool stores sell compression gauges that are junk out of the box (one store happens to come to mind frequently).

If you do not own a known good one (even if it is new from one of the above discount tool stores) many auto parts stores loan or rent quality tools including reliable compression gauges.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Hard to make any comment without knowing what engine you are working on.
 

hadaveha

Petty Officer 1st Class
Joined
Mar 17, 2009
Messages
389
I'm sorry guys it's a 1990 Johnson 60hp vro grant it I'm not using a great gage but all 3 cylinders are really with in 5 percent, but all 3 are reading just alittle over 100 lbs
 
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