I've just finished my ultimate and the motor will not run correctly. It's set up with the EFlite 370 brushless, the stock gearbox, phoenix 25 esc, and a thunder power 2 cell 2100mah lipo. The motor comes to life but runs extremely rough, like it's jerking. Every once in a while while manipulating the throttle it smooths out and runs normally. Anybody have any ideas?