50204-ZVA-000 Swivel Case Collar - Overview. The 50204-ZVA-000 Swivel Case Collar is a critical component in Honda marine engine systems. It functions within the swivel system to provide a secure rotating connection, ensuring smooth operation and protection of key engine components. Designed for Honda marine engines, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. Specifically engineered as a collar within the swivel case system