Yamaha - Water Pump Repair Kit Cooling System 63D-W0078-01-00. Overview. The Yamaha 63D-W0078-01-00 Water Pump Repair Kit is a complete service kit designed to restore proper cooling system performance in a range of Yamaha outboard engines. The water pump is responsible for circulating water through the engine to maintain safe operating temperatures. Over time, the impeller and internal pump components can wear due to heat, friction, and debris in the water.. Replacing the water pump components