Patent ID: 8475222

Claim:
An outboard engine designed to draw cooling water through a cooling water path by rotating a water pump by means of an engine and to discharge exhaust gas of the engine to an exterior through exhaust paths, comprising: an idling chamber communicating with the exhaust paths and opening to an atmosphere, the exhaust paths in communication with an exhaust expanding chamber; a cooling water communicating path causing the cooling water path to communicate with the idling chamber; and a pressure adjusting valve provided for the cooling water communicating path, the pressure adjusting valve opening the cooling water communicating path when a value of a water pressure in the cooling water path reaches a threshold value, wherein a portion of the cooling water is guided to the idling chamber through the cooling water communicating path by opening the pressure adjusting valve when the value of the water pressure in the cooling water path reaches the threshold value, and wherein when the pressure adjusting valve is closed, the exhaust expanding chamber is adapted to discharge exhaust gas to the idling chamber.