The present invention relates to motor safety devices as used in increasing numbers for the killing of engines or disengaging propulsion units from motors, when there are no operators to maintain control of an apparatus or vehicle such as jet-ski, boat, go-kart and the like or personnel to oversee use of a motorised tool or the like. Motor boat operators on a boat have been known to fall overboard without being detected by the operator of the boat. Such runaway boats have been known to seriously injure the operator of the boat in the water since a runaway boat tends to circle back to the place where the operator has fallen overboard. The present invention is also applicable to other types of equipment such as motorised gymnasium equipment, hand operated power tools, such as agricultural and arboriculturist equipment and wood working tools.