90301-ZW5-U00 Hex (5Mm) Nut - Overview. The 90301-ZW5-U00 Hex (5Mm) Nut is a crucial fastening component used within Honda marine engine systems. This 5mm hexagonal nut serves as a reliable connection point in various assemblies, supporting the structural integrity and functionality of multiple marine engine subsystems. Manufactured to precise factory dimensions and tolerances, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. Gen