Mercury - Water Pump Impeller Repair Kit MerCruiser V6 & V8 Brass Seawater Pump Series Marine Composite & Brass Components 8M0137219. Overview. There's a certain confidence you feel when your cooling system is running exactly the way it should. The engine settles into that familiar rhythm, the boat glides steadier, and you stop thinking about what's happening under the hatch and simply enjoy the water. That's the kind of peace of mind a dependable impeller brings, and why so many boaters stick w