63701-ZZ5-M00ZB Cvr (Lower) Nhb14m - Overview. The 63701-ZZ5-M00ZB Cvr (Lower) Nhb14m is a vital component in Honda marine engine systems. This lower cover serves to protect the internal parts of the engine from elements such as water and debris, while maintaining structural integrity and contributing to the optimal operation of the marine engine. Designed specifically for Honda marine engines, it ensures seamless integration with existing parts, maintaining optimal performance and durability..