i have a heli raptor 50 with an OS50 in it and use OS#8 plugs cool power 15% and 30% cant seem to get it to run with out over heating and in my planes the same thing then i tryed someone at the field not sure what brand but had Castor/ Synthetic mix in it and my plane motor ran 100% better i didn't try it in my heli i hate to run Castor in my heli (makes a big mess ) what do you think

thanks Guy

I guess it depends on whether you'd rather have a good running engine or a cleaner heli

Chances are the other fuel you tried might have had a bit higher oil content than the cool power too. Maybe some of your overheating comes from using that #8 plug which is their second hottest. Going from 15 to 30% nitro is a big jump with the same plug, try a cooler one. Hopefully you're retuning everytime you change fuels, even if it's just a different oil content.