41100-ZVL-900ZB Gear *NH565* Case - Overview. The 41100-ZVL-900ZB Gear *NH565* Case is a critical component of Honda marine engine systems. This gear case assembly supports the gear transmission system, playing an essential role in housing and protecting the internal gears that transfer power to the propeller. By ensuring the proper alignment and secure housing of these gears, it helps maintain optimal engine performance and reliability. Made to Honda's factory specifications, it ensures seamles