i just ran my machine,,,,,its somewhat warm here,and i didnt need to preheat it,BUT,,,,,as i rolled it,it started immediantly,and ran for a bit less than a second,then,just died,it didnt completely shut off,but,close,,,,,,still a problem maybe in the fuel system? also,i ran it on a flat ground surface wide open,level ground 22 mph tops,,,,,,when it comes to a hill,it dies,,,,,,