[Randy115]

Just got motor. Starts easily, sounds good, not been run on boat yet. Need an expert opinion. Three cylinders test at 108-109 lbs. Did test as recommended, engine warm at WOT. However, one cylinder tested at 94 lbs. The motor sat for about three months before I got it. Any suggestions? Should I take head off and look at cylinder? Could it be the head gasket? If rings are bad, should all 4 cylinders be re -ringed? If walls are scored, would it be ok to just fix that one cylinder only, if the others look ok? Thanks for any suggestions.

[Robj]

Welcome to iboats!! The first thing I would do is run it a few times out on the water, not in your driveway. You said it is running good so that should not be an issue. Afterwards I would do a decarb and then retest. Those nos are not that bad, maybe just a little of carbon build-up. Do a search on decarb and you will get lots of info on how to do it. You can use a spray from Evinrude or buy Seafoam.

Have a great day,

Rob.

[Randy115]

Thanks for the info. I will do what you suggested. I am hoping that the number for that cylinder goes up.

[trolli]

I just took my boat with 90 hp evinrude in for same issue. The mechanic told me that it is not really something to worry about yet. Can you let me know if your compression comes back after you run it for a while?