The only thing I can think of is that you have a MAJOR air leak. That is the only way your motor is going to throttle up without you opening the carb.
Is your idle stop screw adjusted properly? You should be able to close the carb enough to slow down the idle.
ORIGINAL: georgealley
hi i have recently bought a hpi mt2 and got a problem the gear in the middle was all burnt out so i replaced it but now when i start the engine it goes of on its own any help would be tratfull thanks alot
george
RESSETTING THE CARB DIDNT WORK ANY HELP PLEASE