91554-ZW9-C01 Pinion Gear Bush - Overview. The 91554-ZW9-C01 Pinion Gear Bush is a critical component designed for Honda marine engine systems, specifically supporting the gear case and extension case assemblies. This bushing reduces friction and wear between the pinion gear and its housing, ensuring smooth mechanical movement and efficient power transmission within the gear system. Manufactured to strict OEM specifications, it ensures seamless integration with existing parts, maintaining optima