Hey Dave, i've got a few questions.
First off, my engine does this weird thing that almost sounds like detonation, but i don't think it is. Heres when that "detonation" happens, i let the engine warm up, then move the stick to full throttle, before it even gets there it "detonates" and sound terrible like the engine is going to rip off the plane and the engine stops. So i richen it up almost 3/4 of a turn so this won't happen, the engine is really rich now and the RPMs suffer. I fly it like that and then fuel up again about 20 minutes after i land. I let the engine come up to temperature and throttle up and it does this "detonation" thing again, so i richen up the high end and fly again, not the engine is really suffering in the RPMs. This happens almost every time i fly now, but i only have to righen it up like 3-4 clicks each time.

Prop: From a 13x6 zinger to a 14x4 Prop Zinger, it happens with any propeller.
Fuel: Powermaster 20/20
Glow Plug: O.S. Type F

Please help, and thanks,
Stefan