My ST G90 flies my TF Corsair pretty well. The issues are that I cannot get a low reliable idle and after reducing throttle back to idle, it takes a minute or more before the engine speed will actually be at idle. I've shot past the field a few times trying to land because the engine won't slow down. It has a bisson pitts on it. With the original muffler it won't do this (better transition and a much lower idle). I blocked one exhaust tube with some cotton wadding and it didn't seem to have much effect. Does anyone have a ST G90 running a pitts muffler with the original carb that runs pretty well? What did you do? I've tried adjusting the low and high ends, but no matter where they are set, It won't run correctly.