Won't stop running
#2
Except,
That all electrically powered RC toys, be they Aircraft, Boats, or Cars, have a transmitter, a receiver, some batteries, one or more servos, one or more motors, and then some type of device to control the speed of the motor(s), commonly called an "ESC" (Electronic Speed Control) .
In that list of parts, given the symptoms you describe, and provided you have good batteries that are actually properly charged, I'll ask you; What do YOU think is the most likely of those to cause the malfunction you are encountering?