90509-ZW5-710 Washer - Overview. The 90509-ZW5-710 Washer is a critical component designed for Honda marine engine systems, specifically fulfilling the role of a thrust bearing washer. Its primary function is to provide mechanical support and maintain proper alignment within the moving parts of the marine engine, ensuring smooth and reliable operation. This washer prevents excessive wear and potential damage to adjacent components by efficiently distributing loads and minimizing friction. Engine