RE: Best fuel for TT PRO-36H/39H(both trashed)
15% is plenty good for learning - Coolpower has worked fine for me. I'm wary of TT engine quality control as I had a 36 a few years ago that only lasted 4 gals. before it lost compression - and pretty much everyone at the field said "no surprise." The OS 32 that replaced it had no problems for many gallons. Just run the engine on the rich side to be safe like you've been doing - you don't need lots of power when learning anyway. Hopefully you'll get a good one this time.