Yamaha - Outer Plate Cartridge Water Pump System 6E0-44323-40-00. Overview. When you're inside a Yamaha water pump, the outer plate is one of those parts that quietly keeps everything working right. It helps maintain the proper surface for the impeller to do its job, and once it gets worn or grooved, you'll start losing efficiency. I've seen pumps that looked fine until you pulled them apart and found the plate chewed up from debris. Replacing it during service helps keep water flow strong and consistent.. Key Features. Smooth Impeller Contact Surface - Provides a clean surface for proper impeller operation and water flow.. Wear-Resistant Construction - Built to handle friction, heat, and debris passing through the pump.. Maintains Pump Efficiency - Helps preserve consistent cooling performance by reducing internal wear.. Direct OEM Fitment - Matches original specifications for proper alignment and easy installation.. Engine & Boat Compatibility. Designed for Yamaha 2-stroke outboard e