90303-ZW1-003 Hex Nut - Overview. The 90303-ZW1-003 Hex Nut is a critical fastening component designed for Honda marine engine systems, particularly used within the cooling and water pump assemblies of 75 and 90 horsepower models. This hexagonal nut ensures that essential parts such as impellers and housings are securely mounted, preserving the integrity and efficient operation of the engine system. Manufactured to strict OEM standards, it ensures seamless integration with existing parts, mainta