Ok Guys, the first thing you need to do is ajdust your End Point Adjustment(EPA) on your radio to be sure the servo is allowing the throttle to close completely..(Read your radio manual for instructions). If that does not allow your throttle to close completely then disconnect your linkage from the arm on the carb abd from the servo arm and look for binding(Most Likey The Pivot Near the Tank is too tight), while the linkage is off check that the throttle barrel will close completely.

Using 30% Nitro will natrually raise your idle and create more power. You should add shim to your head button to lower your comression abit, the engine will last longer. You should be able to tune the high idle out. I have never used nitro content that high so I can help you much with your tune, sorry..

I do hope what I have offered does help some tho..

Good luck and have fun!!

PS. let us know how it works out with your fuel choice...

EDIT ADDED: Hey I just noticed CEN was here!! Hey guys hows it going?? Been busy???