40106-ZW9-630 Oil Case Grommet B - Overview. The 40106-ZW9-630 Oil Case Grommet B is a crucial sealing component within Honda marine engine systems. As a durable rubber seal integrated into the oil case system, it helps prevent oil leaks which can compromise engine lubrication and performance. Designed specifically for Honda marine engines, this part plays an essential role in maintaining the engine's reliability and longevity by ensuring a watertight barrier that protects internal engine compon