90301-473-003 U (6Mm) Nut - Overview. The 90301-473-003 U (6Mm) Nut is a genuine Honda marine engine system component designed to securely fasten parts in assemblies requiring a 6mm nut. It supports the mechanical fastening system within Honda marine engines or associated equipment, playing a crucial role in maintaining reliability and performance. By precisely matching factory specifications, this nut ensures seamless integration with existing hardware, preserving the integrity and durability o