Audie-

One thing that I don't think the others mentioned, the "unburnt fuel" you said you are cleaning off the plane does not mean it's running too rich. It is not unburnt fuel, it is the oil from the fuel that does not burn as part of the combustion process. With a glow powered engine, you will always have a substantial amount of oil to clean off of the plane. Do NOT try to lean it out to the point that you have no residue. You will destroy the engine.

To set the mixture, have a helper restrain the plane and give it full throttle. Then slowly turn the needle valve clockwise. Your RPMs should increase up to a point and then back down. Adjust it to the point of maximum RPMs (which you can tell by ear). Then back it off about 2-3 clicks. That is the proper setting for flight.

-Scott