90031-PNA-004 Bolt-Washer (10X30) - Overview. The 90031-PNA-004 Bolt-Washer (10X30) is a critical fastener component designed specifically for Honda marine engine systems. Serving as a vital hardware piece, it supports proper assembly and mounting functions crucial for maintaining the integrity and reliability of marine engine components. Manufactured to strict factory specifications, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Featur