Patent ID: 7168999

Claim:
In a water jet propulsion-driven personal watercraft of the type which comprises: a hull; a hollow pump chamber disposed at a rear portion of the hull; a water jet pump disposed in the pump chamber; an engine disposed in the hull and operatively connected to the water jet pump, the engine serving as a drive power source for the water jet propulsion-driven watercraft; and an exhaust pipe extending from the engine and comprising an exhaust port, the exhaust port of the exhaust pipe being arranged to face the pump chamber; the improvement comprising an improved exhaust gate valve structure, comprising: a valve body for opening or closing the exhaust port; a pressure device for pressing the valve body into a state of closing the exhaust port; and a jet water expelling device, operable to divert part of the jet water from the water jet pump, and to expel the diverted jet water onto the valve body to overcome the force of the pressure device, and thereby force the valve body open.