I bought an RCGF 15 from the local distributor.
After a few tries I got it started but it immediately got very hot so I shut it down.
It was very hard to turn over so I decided to disassemble it and see what happened.
The bottom end was full of black crud. I cleaned it out and it seems to be a lot better. I will try it again tomorrow.
They don't lube it at the factory with graphite do they?

No, black is the color of rubbing aluminum.

Check the timing if it overheated, too advanced will make it hard to start and run hot.

were you able to see if the piston or cylinder wall was scored?

dirtybird,

Who did you buy it from?

I didn't take that apart. It doesn't look bad in the exhaust port.
I think its not a good idea to use a starter on this engine. There is evidence that the end of the shaft rubbed on the back plate.

Superstition Hobbies in Queen Creek AZ.

www.superstitionhobbies.com

not a good sign... thats prolly where all that black crud came from.... clearish black that when you rub it between your fingers disappears is normal, but BAD when it smears like crap all over your fingers and stays black

It certainly is the bad crap. There is a lot of it still on the cloth I used to wipe it out with.
The engine still is very stiff. I am going to put some time on it today and see if it loosens up. That is if I can get it to start by hand. If I can't get it to run OK I am going to get my money back. Its supposed to have a two year warren tee.

Set to run slobbery rich, with maybe an extra couple drops of oil in the first couple of tankfuls to help rinse it out?

I just ran in an RCGF 20 that didn't feel the greatest prior to starting it a few weeks ago. I took the back plate off just to check it out prior to even starting it I was so concerned. Happy to say that after a couple tankfuls of fuel on the ground it felt good enough to launch it. Now, after 15 or 20 more tankfuls, it's fine. Very happy with the engine. But I did do as mentioned to head off/try to prevent any potential issues. Could have all been in my head for all I know though. I didn't see a thing when I took it apart, though I did add a drop of oil to both ends of the rod and cyl. wall when I had it apart? FWIW

The engine wants to run but its just too stiff. The housing for the rod bearings is contacting the back plate and makes it hard to turn. I am going to make another gasket for the back plate and see if that provides enough clearance to stop the rubbing.

How about trying to pull the crank further into the case? A properly sized socket and a washer that would allow you to push on the case when the prop nut was drawn down on it? Don't get too carried away, but you might feel it move a little as you tighten the nut down, but no tighter than you would if you were tightening the nut down on a prop!

[8D] I will attempt to post a link to all I know about the RCGF 15 ..............

http://rctruth.com/index.php?topic=192.0

The problem turned out to be the bearing in the bottom end of the rod is migrating to the back of the engine.
I was able to push it back into place with a piece of brass tubing and a smack with the hammer. I don't guess it will stay where it is supposed to be. Its probably pressed in but in my case it is not a tight enough fit to keep it in place. The only real cure will be a new rod that has the correct fit. I don't suppose lock tite would stand up to the temperature in there.
Does anyone know if there is anything I could put on there to keep it in place?

These are probably aluminum deposits. A common problem in these engines is the crank rubbing up against the back cover. Loosen the back cover bolts and if the engine spins freely, the end cap on the crank shaft hasn't been fitted properly and is rubbing.
Easy to fix with either Loctite 609 or in extreme cases, a spot of Tig weld

i got a rcgf 15 from a local dealer ran 3 tanks of fuel runs good and strong but has a little black oil like coming out the muffler runs cool may be ill call the dealer tomorrow but i like the engine have not tried to had start used a starter starts 3rd flip allen

The black is normal, all of mine started out doing that. It will not be as easily seen as time goes on and the engine breaks in more.

I disassembled the engine and I don't see how you could fix it with loctite without gumming up the needle bearings. Its a design flaw that needs to be fixed. Its going back to the distributor if he will take it.