90442-397-000 Washer (6mm) - Overview. The 90442-397-000 Washer (6mm) is an essential component in Honda marine engine systems, supporting sealing functions to maintain system integrity and prevent leaks. It is designed specifically for use in various sealing applications in Honda engines, ensuring reliable sealing performance and protection against abrasion or loosening of fastened parts. As a crucial part of the marine engine's sealing system, it helps uphold the operational reliability of the