Mercury - Water Pump Repair Kit Cooling System Marine-Grade Components 8M0205802. Overview. When you spend your weekends on the water, you learn quickly that a dependable cooling system is the heartbeat of any outboard. It's what keeps the engine steady when you're cruising across open chop or easing into a quiet inlet at sunset. Knowing your water pump is healthy brings a sense of calm - that reassuring feeling that your engine is running cool, smooth, and protected. That's exactly the peace of