Abstract: The invention provides a system applicable to various internal combustion engines, such as for automobiles, motorcycles, snowmobiles and outboards, to permit an authorized person, such as a police officer, to prevent their improper or illegal operation. The engine includes a detector detecting the speed of operation of the motor which is compared with a preset value. Upon an unusually high motor speed being reached a receiver is enabled for a preset period of time. During this preset period the engine can be disabled by a transmission from a transmitter operated by the police officer, preferably using a designated exclusive channel. The disabling slows the engine to an idle speed without stopping it, so that the power assist mechanisms of the vehicle remain operative to maintain normal braking and steering function.