Laefd,
Yep sounds like an air leak some place. I'm reading all the TT Pro .61 threads to get an idea of what people are up against since I bought a TT pro .61 for my Aero tug Kadet sr Arf.

Same ole same ole, people cant start them, some people say they run hot some people cant get an idle or a mid range, nobody complains about the top end infact everyone says the TT pro will out turn the OS SX. Interesting.

I guess these engines are like anyone eleses engines it all depends on what you like and how you learned to run and care for model engines.

Good luck

JDS