Mercury - Water Pump Housing Sea Water Pump Component Brass Construction 8M0139984. Overview. Out on the water, you get a feel for the parts you can trust. When your cooling system is doing its job, the engine settles into that steady rhythm you can feel through the deck-strong, smooth, and unbothered by long runs or tight maneuvering. The Mercury 8M0139984 Brass Water Pump Housing delivers that kind of confidence. Built for the V6 and V8 MerCruiser sterndrive engines many boaters depend on, thi