9-1/2 hp compression test

[dfrants]

did a compression test on a 1967 9-1/2hp Johnson. it is only 60 psi in each cylinder. seems really low. motor starts and trolls in a barrel pretty well. shouldn't the compression be around 120 psi? is replacing the rings difficult? can someone post repair instructions?

 

[boobie]

Give it a good de-carb and then check the compression again. May even want to try another gauge.

 

[Crosbyman]

See Compression on Leroy's site

http://www.leeroysramblings.com/OMC_9.5.htm

 

[F_R]

You asked if it is difficult to replace the rings. The answer is a big Yes. The whole motor must first be shucked out of the outer shell that it floats in. Very intimidating job for the novice, a big time consumer even for the experienced. And many cuss words are required if it has been used in salt water. A factory service manual is a definite must for the novice. Now that I've said all that, I still like those motors.