First off, the engine is a new Evolution 26GT2, with a fully charged 2c lipo on ignition. I have run the engine in according to Pe and others advice at 30:1 for 1 gallon on the ground so far. I'm getting about 8300 RPM with a bisson muffler (engine is side mounted). Transition is great on the ground, and have had no problems thus far. Last weekend I finally got the airplane to the field, started and warmed up with no problems...RPM stable, transition smooth, good idle. When I took to the air (maiden for airplane and engine) and made got her flying, I noticed that the engine would "bog", for lack of a better term, at full throttle. 5/8 to 3/4 throttle seemed fine, but when advanced I would loose RPM. Transition was still good up to that point, and it didn't die, but never got a full throttle response. Flight time was less than 5 minutes due to this, and haven't had another chance to get it in the air since.

How do I figure out whether I went lean in the air, or if I was too rich? It ran good on the ground after, so I'm a little unsure of which way to go. I realize that this is a very open ended question, so I'm just looking for possibilities.

Weather that day was hot...nearly 90 deg F and roughly 95% humidity, with a storm on the horizon. Engine didn't feel hotter than normal (forgot my infrared temp gun) and I don't believe I was hot, due to short run time. The plug coloration is just a hair darker than perfect. And I am still running a 30:1 mix (Yamalube synthetic racing blend) w/92 octane (US) gas.