Sticky Piston Ring

[biffagump]

I have a 2001 Johnson 115 hp, 4 cylinder. Appears that the rings are sticking in one cylinder (low compression). I don't think it is a head gasket problem, just sticky rings. Any suggestions as to how to "unstick" them?

 

[Scaaty]

Re: Sticky Piston Ring

See the FAQ section on De-Carbing for starts..

 

[Walker]

Re: Sticky Piston Ring

I wouldn't even mess with a decarb. I'd pull the head and take a look.

 

[biffagump]

Re: Sticky Piston Ring

See the FAQ section on De-Carbing for starts..

I have this motor on a 17' C/C boat. I guess I am wondering what the performance symtoms of a blown head gasket vs. symptoms of a sticky ring would be ? Boat idles rough (practically not at all) but when you step on it, it stands right up and goes, no hesitation, no miss at all. Goes up to 5000 rpm in a heartbeat. Seems like it wouldn't do that if I had a blown head gasket. Also, no visible signs of water mixed with oil on spark plug or in combustion chamber. Top of piston has normal amount of carbon rather than being clean as if I had water going in the cylinder. Any feedback is much appreciated.

 

[Scaaty]

Re: Sticky Piston Ring

Why not TRY a Decarb first? Can of spray Seafoam, tilt the motor up and off to the offending side,(well, actually do all jugs), let it sit overnight or a couple days would be better. Then try it. Cost would be 5 bucks. I decarbed my 125 after too long a wait, and went from falling off plane under 3500, to falling off at 3000.
But I should ask first, have you done a compression check? Good place to start.

 

[biffagump]

Re: Sticky Piston Ring

Why not TRY a Decarb first? Can of spray Seafoam, tilt the motor up and off to the offending side,(well, actually do all jugs), let it sit overnight or a couple days would be better. Then try it. Cost would be 5 bucks. I decarbed my 125 after too long a wait, and went from falling off plane under 3500, to falling off at 3000.
But I should ask first, have you done a compression check? Good place to start.

UPDATE: Did a decarb on motor. Started it. Running rough, won't idle. Decided to take the plug out of "problem cylinder" and see if I could run it just a bit to blow out any carbon. Started motor, idled perfect, ran smooth. I put my hand over the cylinder without spark plug while running and I came away with a wet hand. Not alot of water, but most definitely there. This motor has no "head gasket" , just has individual O-Rings for each cylinder. Question is: How common is it for these O-Rings to "go bad", break ? or...is it more probable that I have a more serious problem, holed piston, cracked cylinder? Thanks

 

[Scaaty]

Re: Sticky Piston Ring

Well, now the head has to come off. Not a big job, but you will need to pull it and have a good look-see in there

 

[biffagump]

Re: Sticky Piston Ring

Well, now the head has to come off. Not a big job, but you will need to pull it and have a good look-see in there

Took the head off. O-Ring on the top cylinder was shot. Only about 1/2 of it remained. O-Ring on the bottom cylinder is about 1/3 gone. The top cylinder is scored on the top and I intend to hone that out, put new O-Rings in and see how we do.
Any thoughts?
I DO think that this is something that ought to be passed on as far as maintaining/replacing O-Rings. If I replace the two on the one side, and get the compression back on the top cylinder; I will definitely replace both O-Rings on the other side.
Side Note: Before removing the head, I checked torque on every bolt. They were ALL right where they should be; about 20 lbs.

 

[wisechips]

Re: Sticky Piston Ring

Sounds like you have found the problem . Get her ready for the big fish.