40106-ZW9-830 Oil Case Grommet B - Overview. The 40106-ZW9-830 Oil Case Grommet B is a crucial OEM rubber seal designed specifically for Honda marine engine systems. Its primary role is to provide a tight seal within the oil case system, preventing oil leaks and preserving the lubrication integrity essential for reliable engine function. By effectively sealing the oil case, this grommet helps maintain system pressure and prevents contamination from external elements, ensuring seamless integratio