90515-921-000 Pipe Inner Washer - Overview. The 90515-921-000 Pipe Inner Washer is a genuine OEM part designed to support the Honda marine fuel system. This washer plays a vital role in providing a secure seal and spacing in the inner pipe assembly, essential for maintaining proper fuel flow and preventing leaks inside the marine engine system. Its precise engineering ensures seamless integration with other components, contributing to the reliable operation and longevity of your Honda marine eng