85HP Stuck Ring

[chuckz]

I purchased a used Force 85HP I was told it was a runner. After much troubleshooting I have discovered low compression. As part of maintanence I had the heads off and replaced the head gasket. The original machining marks were still in the cylinders. There was no carbon in the rings where I could see them. I suspect the rings are not seating because of being glued in place by old gas. After I tried to start this engine, I realized it hadn't been started in years. I had put oil in the cylinders, Deep Creep, before trying to start it. What is the best way to get the rings unstuck?

 

[roscoe]

Re: 85HP Stuck Ring

soak it with deep creep, adding a spray in each cylinder every hour or so.

 

[chuckz]

Re: 85HP Stuck Ring

Thanks Roscoe. Right now I have the engine tilted up and Marvel Mystery Oil in the cylinder. Tomorrow I'll use Deep Creep and/or Seafoam.

 

[eurolarva]

Re: 85HP Stuck Ring

I have had more luck with the Marvel Mystery oil then with seafoam. If you have the head off the boat and tore apart the carbon is more noticable through the exhaust ports. Stuff rags saturated with mystery oil and let it soak over night then chisel away the carbon with a wooden stick.

 

[chuckz]

Re: 85HP Stuck Ring

The head is back on. There was no carbon. I didn't pull the pistons out because I was told the engine was a runner. The motor is on the boat now and I rather not tear it down again if I can avoid it.

 

[novicetech]

Re: 85HP Stuck Ring

What are the compression numbers?

 

[chuckz]

Re: 85HP Stuck Ring

Well all summer I have been working on freeing up the rings. Marvel mystery oil freed up #3 almost immediately and the compression is 120 pound. #1 got up to 95 and #2 is lagged behind at 50 pounds. Nothing else has made any improvment. I've used Seafoam, Deep Creep, PB Blaster, acetone and Silikroil. Dissolved gum has stopped running out of the carbs when the engine is tilted all the way up but no increase in compression.<br /><br />I'm going to tear the powerhead down and pull the pistons. I'll let you know what I find.<br /><br />Incidently, I did complete a lot of trailer work and other upgrades to the boat. I've been fortunate to be able to go boating with one of my buddies so the summer was not a loss.

 

[t.martin]

Re: 85HP Stuck Ring

I have a bunch of parts if you need them.

 

[chuckz]

Re: 85HP Stuck Ring

Thanks t.martin. I have an extra set of carbs and a complete ignition system. I think the only thing I might need is a new set of rings.

 

[chuckz]

Re: 85HP Stuck Ring

I ended up pulling the pistons outs. The rings were absolutely locked into the grooves. After soaking the pistons in various solvents to no avail, I ended up prying the rings out.

I cleaned the grooves, installed new rings and reassembled. After charging the battery the engine fired right up.

 

[roscoe]

Re: 85HP Stuck Ring

Thanks for the update.
Glad you got her running.

Happy Boating.