16800-ZW5-003 Water Separator - Overview. The 16800-ZW5-003 Water Separator is an essential OEM component in Honda marine engine systems. It plays a critical role in the fuel system by effectively separating water and debris from the fuel before it reaches the engine. This ensures cleaner fuel delivery, which is vital for efficient combustion, smoother engine operation, and extended engine life. Designed to meet exact factory specifications, the water separator seamlessly integrates with existin