Quicksilver 807166A1 Water Shutter For MerCruiser V6 & V8 Engines With 2-Piece Exhaust ManifoldsWater shutter designed to prevent water from backing into the engine through the exhaust on MerCruiser V6 and V8 engines with 2-piece exhaust manifolds. Acts as a check valve during low RPM or engine shutdown.Features Fits 1995 & newer MerCruiser V6 & V8 engines with 2-piece exhaust manifolds; Helps prevent water intrusion into engine via exhaust; 2.48 in. diameter at cross pin (hinge pin); Acts as a check valve at low RPM or when engine is off; Built to Mercury Marine OEM standards; See your owner's or service manual for fitment; Replaces Pro Marine - 65167;