94109-20000 Drain (20mm) Washer - Overview. The 94109-20000 Drain (20mm) Washer is an OEM replacement part designed for Honda marine engine systems, specifically serving as a sealing component in the drain system. This essential part helps prevent leaks at drain points by providing a durable, aluminum crush washer that conforms precisely to factory specifications, dimensions, and tolerances. It ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key