13621-ZY9-000 Sprocket (23T) - Overview. The 13621-ZY9-000 Sprocket (23T) is an essential component in Honda marine engine systems. This 23-tooth sprocket plays a crucial role in the cam chain system, supporting reliable mechanical motion and efficient power transfer within the engine's timing mechanism. Specifically designed to match the factory specifications, dimensions, and tolerances, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key F