18337-ZW4-000 Exhaust Pipe Grommet - Overview. The 18337-ZW4-000 Exhaust Pipe Grommet is a critical rubber component used in Honda marine engine exhaust systems. Serving to securely seal and isolate the exhaust pipe, it prevents exhaust leaks and reduces engine vibration, helping maintain efficient and safe engine operation. This grommet is designed to seamlessly fit with factory parts, ensuring optimal performance and durability in demanding marine environments.. Key Features. Grommet specifica