Hello,
I'm running a 10% Jets Nitro (
http://rcshop.uits.bg/images/5L-JETS.jpeg).
Yes, I do leave the engine to heat up before tuning. The fact is, that with 89F degrees outside temperature, the engine heats up pretty quickly. Overall I'd say it runs as smooth as silk - it's just that once you kill the engine you can't start it again (dead plug).