The engine may be running too lean. Open the needles 1/4 turn or gun the engine on the ground and using a tach, decrease the rpm by 300 kliks by richening the high speed needle.
Full throttle...hold the nose up 45 degs and if the rpm decreases...it's still too lean, richen the high speed needle.
IF that does not help.....put the engine back in the box where it belongs [8D]
A student at our club recently bought one new, same problem after two months. In the beginning though....the carb was leaking..so check that seal. It is baffling why that engine gets over heated.