90305-ZV4-000 Self-Lock (8mm) Nut - Overview. The 90305-ZV4-000 Self-Lock (8mm) Nut is a critical hardware component designed for Honda marine engine systems. This nut functions to securely fasten parts by using a self-locking mechanism that prevents loosening under vibration and movement. By maintaining stable and reliable connections, it helps ensure the marine engine operates safely and efficiently. Crafted to OEM standards, it ensures seamless integration with existing parts, maintaining opt