90021-ZV4-003 Hex (6x25) Bolt - Overview. The 90021-ZV4-003 Hex (6x25) Bolt is an essential fastening component used in Honda marine engine systems. This bolt is designed to secure various engine parts reliably, helping maintain the structural integrity and functionality of the marine engine. Its 6x25mm hex head design ensures compatibility with specific mounting points, providing a robust and durable connection that withstands marine conditions. Precisely crafted to OEM standards, it ensures se