Yamaha - Water Tube 1 Cooling System Component 6S1-44361-02-00. Overview. Water tubes are one of those parts you don't notice until cooling becomes a problem. I've seen engines start running hot just because water flow wasn't getting where it needed to go. When the tube is solid and clear, the cooling system does its job and keeps temps in check. It's a simple piece, but it's critical for keeping the engine running safely over long days.. Key Features. • Consistent Water Flow - Directs cooling water through the engine to regulate temperature.• OEM Fit and Routing - Designed to match factory layout for proper alignment and installation.• Corrosion-Resistant Build - Built to handle constant water exposure in marine environments.• Cooling System Support - Helps maintain stable engine temperatures during operation.. Engine & Boat Compatibility. Designed for Yamaha outboard engines utilizing internal water cooling systems. Commonly used across a range of Yamaha outboards where proper water