Well, I took the cub out again today and it is flying very well but I am still having engine problems. I knew that the overheating was a problem so I flew it today with the cowling off. That helped tremendously but then I started having another problem. I can takeoff and fly around as long as I want and the engine works fine however when I lower the throttle below about 25% it will quit. This happens every single time and as a result all of my landings so far have been dead stick. It doesn't ever do this on the ground, just in the air.

The engine is a K&B 65 and it is mounted inverted. I am using the Top Flite in-cowl muffler. Like I said, it runs fine on the ground and it will run fine in the air until I lower the throttle. I don't even have to bring it down to idle, anything below 1/4 and it will die. The needles appear to be set right and it is running slightly on the rich side. Has anybody ever seen this before?

By the way, this has to be the messiest engine I have ever seen. It spits tons of fuel out of everywhere.