Abstract: The electronic winterizer is a device that is installed in the interior of a boat. It winterizes an inboard/outboard engine without the use of a person knowledgeable of this process. It can be accomplished in or out of the water. The invention allows a boat owner to operate his inboard/outboard engine in cold temperatures without having to employ a person to winterize the engine each time he uses it. Thus it is made useful all winter. To operate, the inboard/outboard engine is first started. After the engine reaches an acceptable temperature, the thermostat is opened. While the engine is running the operator turns on a switch that is mounted in the dash of the driver's console. The switch activates an electronic timer that operates a DC powered valve and pump. At the time of operation the valve opens and the pump starts. The pump drains antifreeze from a holding tank that is also installed in the boat's interior. The pump dispenses antifreeze through the open valve and into the injector.