90009-ZW9-000 Flange (6X23) Bolt - Overview. The 90009-ZW9-000 flange (6X23) bolt is a critical fastening component used in Honda marine engine systems, primarily within gear case and extension case assemblies. This OEM bolt supports the structural integrity of the engine by providing a reliable mounting solution, ensuring parts remain securely fastened during operation. Designed specifically for use in Honda marine engines, it ensures seamless integration with existing parts, maintaining optima