Mercury - Water Pump Impeller Cooling System Premium Elastomer 8M0186795. Overview. Every boater knows the quiet relief that comes from glancing at the temperature gauge and seeing everything right where it should be. No unexpected spikes, no uneasy buzz in the back of your mind-just steady, dependable cooling doing its job while you focus on the horizon. That kind of confidence doesn't come by chance; it comes from parts that work hard behind the scenes. The Quicksilver 8M0186795 Water Pump Imp