13621-ZY9-H01 Sprocket (23T) - Overview. The 13621-ZY9-H01 Sprocket (23T) is a critical component in the cam chain system of Honda marine engine systems. This sprocket plays a vital role in the power transmission mechanism, ensuring the smooth and precise operation of the cam chain that drives the engine's timing functions. Designed specifically for use in Honda Active Marine engines, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Featur