90757-921-000 Split (3Mm) Pin - Overview. The 90757-921-000 Split (3Mm) Pin is a precision-engineered component used within Honda marine engine systems. Specifically, it functions as a reliable cotter pin or split pin designed to secure components by locking fasteners in place, preventing loosening under vibration or mechanical stress. This pin belongs to the fastener system and plays a crucial role in maintaining secure connections in rigging and accessory assemblies, ensuring seamless operatio