Like you, I have a couple of the Tower .75's and they are really good engines. I have a 46 that was a bugger to tune until I figured out that the low end is pretty sensitive. SMALL ADJUSTMENTS ONLY PLEASE. The other issue, going lean in flight was cured by sealing up the muffler pieces with high temp silicone and high temp lock tite. After that mine is still burning up the sky on a shrike 40. This same 46 was on my wife's trainer until she begged for a 4 stroke. It seems like the Tower 46 is like the Magnum 46 and 52 in that the carb really likes small adjustments. Good luck and enjoy