Yamaha - Water Tube Cooling System Component 6D8-44361-20-00. Overview. The Yamaha Water Tube 6D8-44361-20-00 plays a key role in moving cooling water from the lower unit up into the engine. It may seem simple, but if this tube becomes clogged, bent, or damaged, it can reduce water flow and lead to overheating. It works as a direct pathway for cooling water, so keeping it in good condition is essential for maintaining proper engine temperature and performance.. Key Features. • Direct Water Flow Channel - Transfers cooling water from the lower unit to the engine.. • OEM Fit Precision - Built to Yamaha specifications for proper alignment and secure fit.. • Supports Cooling Efficiency - Helps maintain consistent water circulation to prevent overheating.. • Durable Construction - Designed to withstand heat, pressure, and marine conditions.. Engine & Boat Compatibility. Verify compatibility with your specific Yamaha engine model and part number before installation.. FAQs. Q1: What does a wa