compression spec for yamaha 55 1993

schmalts

Cadet
Joined
Sep 29, 2009
Messages
8
Hi, anyone have the compression spec for a yamaha 55hp 1993 model? that is the 2 cyl model. I am thinking of buying one but want to test compression before I buy.
any thoughts on the reliability of these motors?
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: compression spec for yamaha 55 1993

There is no psi spec, schmalts.

Look for the cylinders to be within 10% of each other. Depending on your guage, technique and conditions you might get as high a 120-130 or as low as 80-90.

Good luck. :)
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Re: compression spec for yamaha 55 1993

Always a good idea to run the motor on the boat, in the river, before buying it. Run it wide open for a few minutes, then at mid-range, then at idle. If it does all these well, then it may be a good motor. Good Luck!
 
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