Yamaha - Water Pump Gasket Cooling System Seal 6H3-44315-A0-00. Overview. Water pump issues don't always come from the impeller-sometimes it's a simple gasket that's not sealing right. I've seen small leaks or air gaps throw off cooling performance more than people expect. When this gasket wears out, you can lose pressure in the system and start running hotter than normal. It's a small part, but it plays a big role in keeping the cooling system tight and working properly.. Key Features. Seals Water Pump Housing - Prevents leaks and maintains proper cooling system pressure.. Precision Fit Design - Matches Yamaha specifications for accurate alignment and sealing.. Heat-Resistant Material - Built to withstand constant exposure to temperature changes.. Supports Efficient Cooling - Helps ensure consistent water flow through the engine.. Ideal for Service Replacement - Commonly replaced during water pump maintenance.. Engine & Boat Compatibility. Designed for Yamaha outboard engines with com