Yamaha - Water Pump Repair Kit Cooling System Service Kit 6E5-W0078-1A-00. Overview. On these Yamahas, the water pump is one of the first things I check if there's any question about engine temp. I've seen good motors get cooked just because the pump wasn't serviced in time. This kit is what you use to bring the cooling system back to life without cutting corners. Once it's done right, you get solid water flow and peace of mind every time you fire it up.. Key Features. • Complete Water Pump Serv