90306-ZV4-000 Hex (8mm) Nut - Overview. The 90306-ZV4-000 Hex (8mm) Nut is an essential fastening component used in Honda marine engine systems. It plays a critical role in securely fastening parts within the rigging and accessory systems of the marine engine, ensuring the equipment operates reliably. Manufactured to match Honda's strict factory specifications, this hex nut ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. 8mm hex nu