90302-ZV4-000 Self-lock (5mm) Nut - Overview. The 90302-ZV4-000 Self-lock (5mm) Nut is a vital hardware component used within Honda marine engine systems. This self-locking nut is designed to provide a secure fastening solution that prevents loosening caused by vibration and operation stresses typical in marine environments. Supporting Honda's marine rigging and accessories system, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features.