Yamaha - Water Tube Cooling System 6D8-44361-00-00. Overview. This is one of those parts that quietly keeps your engine alive every time you run it. The water tube carries cooling water from the pump up into the powerhead, and if it's not right, the whole system suffers. I've seen overheating issues come down to a tube that was slightly bent or corroded. Keeping this piece in good shape makes sure your engine stays cool and runs the way it should.. Key Features. Consistent Cooling Water Flow - Transfers water efficiently from the pump to the engine.. Rigid Tube Construction - Maintains proper alignment under vibration and engine movement.. Corrosion-Resistant Material - Built to withstand long-term exposure to marine environments.. OEM Precision Fitment - Matches original specifications for proper routing and installation.. Engine & Boat Compatibility. Designed for Yamaha outboard engines with standard cooling systems. Commonly used on small to mid-range horsepower motors found on skif