Yamaha - Water Pump Repair Kit Cooling System Service Kit 6E5-W0078-A1-00. Overview. On older two-stroke Yamahas, the water pump is something you don't gamble with. I've seen engines from this era run great for years just because the pump was serviced on time. This kit gives you everything you need to freshen it up and keep water moving like it should. Do it right, and you avoid overheating problems that can take a good motor down fast.. Key Features. • Complete Cooling System Kit - Includes all key components needed for a full water pump service.• Strong Water Flow Restoration - Helps bring cooling performance back to proper operating levels.• Two-Stroke Specific Components - Designed to match older Yamaha two-stroke pump systems.• Durable Marine-Grade Materials - Built to handle heat, debris, and continuous water exposure.• All-in-One Service Solution - Eliminates guesswork by providing matched parts for proper assembly.. Engine & Boat Compatibility. Designed for Yamaha two-stroke ou