90751-ZV4-C21 Spring (3.0X22) Pin - Overview. The 90751-ZV4-C21 Spring (3.0X22) Pin is a crucial fastening component used in Honda marine engine systems. This spring pin provides secure mechanical retention within the engine's swivel case and related assemblies, ensuring reliable operation under demanding marine environments. It is engineered to meet strict factory specifications, guaranteeing seamless integration with existing parts, maintaining optimal performance and durability.. Key Features