Mercury - Water Pump Assembly V6 & V8 Sterndrive Cooling OEM Housing & Components 8M0113734. Overview. Anyone who's spent long days running a MerCruiser engine knows how much trust you place in your cooling system. When the water pump is healthy, the boat feels different - the engine settles into a steady hum, the throttle feels smoother, and you stop thinking about temperature gauges altogether. That's the kind of quiet confidence the Mercury 8M0113734 Water Pump delivers. For V6 and V8 sterndr