# Craftsman Leaf Blower



## jsouth (Jan 31, 2008)

This 2 cycle leaf blower has low compression.Took the engine apart and found it had a stuck ring.The piston and cylinder looks good.My question is how do you loosen a stuck ring.I have soak the piston in MMO and sea foam for a couple of days, with no results.Now I using transmission fluid and acetone,I found this on line from other people,so far the ring is still stuck.I,m out of ideas.I also put the piston in my ultrasonic cleaner with simple green,before I did the above.The piston is really clean no carbon,but the ring is still STUCK.

Thanks,
Jerry


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## paulr44 (Oct 14, 2008)

Safety Kleen cold-soak, AKA carb. soak tank. Comes in 5 gal. pail about 4 gal. in when new, cost over $200. I've put cylinders in it for a day to three while waiting for parts, most combustion deposits fall off or are loose/soft. We've seen the stuck rings as commonplace lately. A certain manufacturer blames it on stale fuel, but the same mfg. blames exhaust port deposit buildup (restricted ex. port) on stale fuel also. Being I've seen a plugged up port on a backpack blower that still had very "free" rings, I have to revert to the research I've done about "stuck rings." Stuck rings in my, and racing documentation information, are due to overheating which relaxes ring tension, allowing the combustion process to collapse the rings, subseuently jamming them retracted with combustion carbon. I've seen "flame wrap" on countless engines, both 2 and 4 stroke, and the piston skirts are charred and/or coated in carbon. So it stands to reason if the rings relax due to overheating, they'll suffer the same consequences as the skirt. I've often also seen cylinder wall coking, in other words either a carbon film or buring effect of the wall. We've had excellent results dolling up the cyl. wall with a glaze breaker and replacing the piston on such units. The same units often have collapsed and often cracked piston crowns, usually a result of improper octane fuel.

We've seen stuck rings in units as young as 1 year old, but usually I'd say it's 2 yrs. or more. One big problem is that the fuel in this country has changed dramatically in the last 30 years, and while we've had gasahol at 10% for years, only within the last 4 yrs. or so have the oil companies been required to use strickly corn-alcohol from what I understand. I account this action to the dramatic increase in carburetor corrosion, but not being a scientist or chemist, I only have a professional related opinion. That doesn't detract from what I see every day, so my opinion therefore does carry weight.

In closing, if you really want to try and re-use a piston with stuck rings, break the rings out, use a piece of the old rings as a groove cleaner to try and chip/scrape the carbon out. Bear in mind, that if you widen the ring land (enlargen the overall height), things won't work the way they are intended and longevity and possibly power will suffer. If you are very careful, you can probably re-use the piston but always replace the rings.

Paul


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## jsouth (Jan 31, 2008)

Thanks,Paul for your reply.I finally got the ring to come free.A friend of mine told me to put the piston in boiling water,for a while and then put the piston ice water.I did this a number of times and the ring came loose.

Jerry


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## paulr44 (Oct 14, 2008)

I understand. Rapid variations in temperature applied to dissimilar metals causes the bond (of carbon) to fracture and release due to dissimilar expansion and contraction rates. I have often used that same principal years ago on Tecumseh muffler bolts that would break off (on the bolt that was actually in the exhaust path, which would rot it out). I'd heat the block around the bolt mounting boss with a propane torch, and ice the bolt remnant, like a stud. Worked most of the time.

Gotta love physics...

Keep it simple!


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