Ok have i been racing today and it has been very hot, i have run my JP and i only seem to get 4 mins, i was going to lean it a bit to get more milage but its runnning hot and i dont want to lean it anymore. I have checked the plug and the bottom is brown to going black and the coils is bright silver but it looks "burnt" were it touches the edge (bottom) of the plug.

Any ideas about what to do would be great!

i have tried another engine and it does the same thing.