Patent ID: 8651908

Claim:
An anti-ingestion system for a marine drive having an internal combustion engine, the system comprising: an exhaust system discharging exhaust at an exhaust outlet below the surface of a body of water in which the marine drive is operating; a cooling system drawing cooling water from the body of water and pumping the cooling water through a water conduit to an exhaust mixing point to discharge into and mix with exhaust from the exhaust system; and a duckbill valve being operated by differential pressure thereacross to a closed condition when the engine is operating in an on state and the cooling water is being pumped through the water conduit to the exhaust mixing point, the duckbill valve in the closed condition blocking passage of cooling water therepast, the duckbill valve being operated by differential pressure thereacross to an open condition when the engine is in an off state and the cooling water is not being pumped through the water conduit to the exhaust mixing point, the duckbill valve in the open condition permitting passage of air therethrough and communication of atmospheric pressure to the exhaust mixing point to relieve vacuum in the exhaust system; wherein the duckbill valve is connected in communication with the water conduit and the duckbill valve in the open condition permits communication of atmospheric pressure to the exhaust mixing point to relieve vacuum in the exhaust system; and a Tee fitting connecting the duckbill valve with the water conduit.