Yamaha - Water Pump Repair Kit Cooling System 6L5-W0078-00-00. Overview. Water pump issues are something you don't want to gamble with-once cooling drops off, it doesn't take long to run into bigger problems. This kit is the kind of rebuild you do to stay ahead of that, especially on smaller two-stroke Yamahas that see regular use. It's a solid refresh that brings water flow back to where it should be without piecing parts together one by one. If you've been running the same pump for a while, th