90603-ZY3-020 Tube (D29) Clamp - Overview. The 90603-ZY3-020 Tube (D29) Clamp is a crucial component within Honda marine engine systems. It is designed specifically to secure D29-sized tubes, playing an essential role in maintaining the stability and correct positioning of these tubes under operational conditions. By preventing movement and vibration, this clamp ensures the overall reliability and efficient performance of the marine system it supports. Crafted to fit seamlessly with existing par