Yamaha - Outer Plate Cartridge Water Pump Housing Component 6H3-44323-40-00. Overview. When you're rebuilding a water pump, the small housing components matter just as much as the impeller. I've seen pumps lose efficiency simply because the wear plates were scored or warped. This outer plate helps keep everything sealed and moving water the way it should. It's one of those parts you replace while you're in there to avoid doing the job twice.. Key Features. Water Pump Housing Support - Forms part of the pump assembly that directs water flow through the system.. Smooth Internal Surface - Helps maintain efficient impeller operation and consistent water movement.. OEM-Spec Fitment - Built to Yamaha dimensions for proper alignment within the pump housing.. Wear-Resistant Design - Designed to handle constant contact and reduce internal scoring over time.. Cooling System Efficiency - Supports proper water circulation to help prevent overheating.. Engine & Boat Compatibility. Designed for Yama