13621-ZW5-003 T/b Drive Pulley - Overview. The 13621-ZW5-003 T/B Drive Pulley is a critical component in Honda marine engine systems, specifically designed for timing belt drive operations. It plays a vital role in maintaining precise synchronization of engine internal components to ensure reliable and efficient performance. Manufactured to match factory specifications, this pulley seamlessly integrates with existing engine parts, preserving optimal operation and durability.. Key Features. The p