Yamaha - Water Pump Repair Kit Cooling System Service Kit 6N6-W0078-00-00. Overview. The Yamaha Water Pump Repair Kit 6N6-W0078-00-00 is one of those kits you grab when you want to fully reset the cooling system instead of patching it piece by piece. On these larger 2-stroke motors, once the pump starts wearing out, you'll usually see it in weak water flow or rising temps under load. This kit gives you the main components to bring everything back to proper working condition. If you're doing maintenance or fixing cooling issues, it's a solid, complete solution.. Key Features. • Complete Pump Service Kit - Includes essential components needed to rebuild and restore water pump performance.. • OEM Fit Precision - Built to Yamaha specifications for proper alignment and reliable operation.. • Restores Cooling Efficiency - Helps bring back strong water flow and stable engine temperatures.. • Durable Marine Components - Designed to handle heat, friction, and continuous marine use.. Engine & Bo