90003-ZW1-305 Bolt - Overview. The 90003-ZW1-305 Bolt is a precision-engineered component specifically designed for Honda marine engine systems. This bolt primarily supports the timing belt cover system, playing a vital role in securely fastening the cover to protect the timing belt mechanism. By maintaining a secure mounting, this bolt ensures seamless operation of the engine's timing system, promoting reliability and longevity. Built to exact OEM specifications, it ensures seamless integration