evinrude 48 compression help

[circlehook69]

What compression readings should I get out of my Evinrude 48spl? Thanks in advance!!

 

[JB]

Re: evinrude 48 compression help

If you do the test exactly as described in the Top Secret File ^^ you should get 100psi or better with both cylinders within 10% of each other.

Remember, psi is not the main issue, matching the cylinders is. The main exception to this is when you have a head gasket failure between the cylinders, then they may both give you 40-50psi.

 

[oldcatamount]

Re: evinrude 48 compression help

There's a wide spread of acceptable numbers for any motor. The main factor is that all cylinders should be within 10% of each other. Your motor would run anywhere from a low of 60 lbs (or so) all the way up to 140 (brand new numbers). What year is the motor and how does it run now? Some motors (that are trolled alot) simply need a de-carb treatment to dissolve some of the carbon inside the cylinders and clean the rings. that will increase the compression a bit.

 

[circlehook69]

Re: evinrude 48 compression help

Thanks....I have a '94 48spl. It runs like a top! I was just curious as to what kind of compression to expect, I've searched the net and couldn't find any numbers on it. Thanks for the info guys!!

 

[boobie]

Re: evinrude 48 compression help

Motor manufactures don't even give out compression specs. Most say no more than 10% or 15 psi variation between cyls.

 

[lmuss53]

Re: evinrude 48 compression help

My old 55 with a fresh dealer ring job (about 25 hours ago) is right at 140 on both cylinders.