90302-921-000 Nut Hex (16MM) - Overview. The 90302-921-000 Nut Hex (16MM) is a vital fastener designed to support Honda marine engine systems within the rigging and accessory components. As an OEM hexagonal nut, it provides secure mounting and reliable connection between parts, ensuring the structural integrity and smooth operation of your marine engine system. Crafted to meet precise factory specifications, this nut fits seamlessly with other hardware, contributing to optimal performance and lo