Yamaha - Water Tube Cooling System 6E0-44361-00-00. Overview. The water tube is one of those parts that just needs to do its job without any issues. It carries cooling water from the lower unit up into the powerhead, and if something's off, the whole cooling system suffers. I've seen bent or corroded tubes cause weak flow and overheating problems that weren't obvious at first. Keeping this piece in good shape is key to making sure your engine stays properly cooled every time you run it.. Key Features. Direct Water Transfer Path - Moves cooling water efficiently from the pump to the engine.. Rigid Tube Construction - Maintains shape and alignment under engine vibration and use.. Corrosion-Resistant Material - Built to withstand constant exposure to water and marine conditions.. OEM Fitment Design - Matches original specifications for proper routing and easy installation.. Engine & Boat Compatibility. Designed for Yamaha 2-stroke outboard engines with standard cooling systems. Commonly u