What are the chances of me un-sticking this apex seal?
 

Hey everyone,
finally found a local 12a for a great price... Came out of a good running GS two months ago, and has been sitting outside with a trash bag on it and motor oil in the housings.
Went and checked it out today, and it had good compression everywhere except one of the rear rotor apex seals was stuck...I physically saw and poked it.

My question is regarding the different methods found when searching to loosen stuck seals...what is the success rate?
It would suck to put it in and have no luck, but it's such a good deal I don't know I'd I can pass it up.

You could put a can of sea foam into the chambers, replace the plugs and point the exhaust ports up, them turn it over by hand several times, let it soak a few hours, turn it again, etc and keep repeating for about a week. Might work.

Success rate is 100% if it works.

If Seafoam doesn't work, then you can try automatic transmission fluid (ATF). Some people worry about ATF softening up some of the soft seals, but it will be fine for this application. If you were letting it soak for weeks/months, then I might worry. ATF is very good at cleaning this kind of thing up.

Think of it this way..the engine is no good as it is. If you can free it up with seafoam or ATF, then that's great. If it doesn't work, then you will have to tear is down to free it up, so you are not out anything by trying everything you can to free up the apex seal from the outside.

So try the soak and continue to work the seals. Turn the engine over periodically during the soak. You can also try to work the stuck seal in/out using a screwdriver or similar through the exhaust port to free it up.

Try the seafoam soak first and move to ATF if it doesn't work.

Good luck.

I think patience is the key here. Go slow and don't damage the seal by poking to hard. Allow the solvents time to work.
Good luck :)

Seaform or ATF as others mentioned. Since you can see the apex that's got the stuck seal, turn the engine so that apex is at the bottom (obviously) and dump your product of choice down the spark plug hole. Let it sit a good day or two. You could turn the engine back and forth a wee tad every so often just to swirl things up a bit.

After enough time's gone by, turn the engine counterclockwise (when looking from the front) to spit the excess out the spark plug holes, reinstall the plugs, and go for a run. If all goes well, hopefully it'll unstick itself.

Assuming it does, you might want to run a couple cans of seaform through the tank (and then a can every so often) just to help clean up any residual carbon over time to keep it from happening again.

Good luck!