90011-ZZ3-030 Head Cover Bolt - Overview. The 90011-ZZ3-030 Head Cover Bolt is an essential fastener designed specifically for Honda marine engine systems. It plays a critical role in securely fastening the head cover to the engine block, ensuring a proper seal that prevents oil leaks and maintains engine integrity. This bolt is engineered to withstand the demanding conditions of marine environments, providing reliable performance and durability. Its precise design guarantees seamless integratio