Yamaha - Water Pump Repair Kit Cooling System Service Kit 6H3-W0078-02-00. Overview. The Yamaha Water Pump Repair Kit 6H3-W0078-02-00 is one of those kits you grab when you want to bring the cooling system back to full strength instead of just swapping the impeller. On these mid-range outboards, once water flow starts dropping off, it usually means more than just one part is worn. This kit gives you the core components to rebuild the pump and restore proper cooling. If you're doing maintenance or chasing overheating issues, it's a solid all-in-one fix.. Key Features. • Complete Pump Rebuild Kit - Includes key components needed to restore water pump performance.. • OEM Fit Precision - Built to Yamaha specifications for proper alignment and reliable operation.. • Restores Cooling Efficiency - Helps bring back strong, consistent water flow through the engine.. • Durable Marine Components - Designed to handle heat, friction, and continuous use.. Engine & Boat Compatibility. • T50 1997-2016