88 Force 85Hp Uneven Compression

[O.T.Water]

Hi All, New to the forum and after what I've read there are so many willing to share ideas I had to join. Just bought a Sportcraft 160 Fisherman w/ Force 85 Hp both 1988 vintage. It sea trialed very well except for stalling while going into gear at idle, but I've read about that in the posts and no biggy. Starts up very well, runs great cruising and WOT. My concern is compression in #1+3 cyls is 140 and #2 is 110. Any ideas on what I might look for to correct this or run it till dead? The boat was just traded recently and I bought it from a marine dealer, he didn't seem too concerned about the difference. I'm looking to get a couple years light duty from this Force and then repower. The boat itself is in great condition and is sitting on a newer aluminum trailer so I got a good deal. Thankx for reading. OT Water

 

[jerryjerry05]

Re: 88 Force 85Hp Uneven Compression

Sea Foam or Mercs Power Tune will help increase the compression.The dealers nonchalant attitude means don't trust him as he knows that the motor will FAIL sooner than later.Low comp to anyone that knows anything about outboards means trouble.
Sounds like the piston rings have carboned up.
You need to fix it as soon as possible as it will go bad soon.J

 

[O.T.Water]

Re: 88 Force 85Hp Uneven Compression

Thankx for the reply, will give that a shot and see if it makes a difference. Do you think it will make an immediate change in comp or will it take a little running to bust the carbon, if that's the issue. OT

 

[john from md]

Re: 88 Force 85Hp Uneven Compression

Follow the procedure in the FAQ on how to do a decarb. If you have to, do it twice and let it sit overnight the second time. Then take it out and go WOT to blast the carbon off of the rings and cylinder.

Don't do any adjustments until after the decarb as you will only have to re do them.

John

 

[O.T.Water]

Re: 88 Force 85Hp Uneven Compression

Thankx, really appreciate the feedback. Have to work 2 weeks straight so it will be a while but I will let you know how I make out.