90021-ZW1-000 Flange (6X106) Bolt - Overview. The 90021-ZW1-000 Flange (6X106) Bolt is a vital component designed specifically for Honda marine engine systems. It plays a crucial role in securely fastening parts within the engine assembly, contributing to the overall structural integrity and reliable operation of your marine engine. Engineered to match precise factory specifications and tolerances, this flange bolt ensures seamless integration with existing parts, maintaining optimal performance