90507-921-000 Nylon (8mm) Washer - Overview. The 90507-921-000 Nylon (8mm) Washer is a genuine Honda marine engine component designed to support the marine rigging system by providing a durable and reliable sealing solution. This nylon washer plays a critical role in maintaining proper mounting and protection of various parts within Honda marine engines, ensuring smooth and dependable operation. Engineered to exact factory specifications, it guarantees seamless integration with existing parts, m