I just bought my first new engine (TT PRO .46) in 20 years. When I ran it on the test stand for the first time, I noticed something very different from my older engines.....the sound. The older motors were "screamers" very loud, very high pitched.

When you went from Rich to Lean, there was a very noticable transition in sound. With the new motors..not so much. they seem to "smooth out" rather than go from the 4 cycle to 2 cycle change in pitch. You have to listen more closely than with older motors.

But they are much quieter and seen to have more power turning a larger prop. I'm not complaining about the new motors, it's just going to take a while for me to train my ears for that "sweet spot".

Anyway, just thought I'd share my thoughts...and I welcome your comments.

Thanks,