30530-ZY6-003 Knock Sensor Assembly - Overview. The 30530-ZY6-003 Knock Sensor Assembly is an essential component in Honda marine engine systems. This sensor detects engine knocking or pinging, providing critical input to the engine control unit to optimize ignition timing. By monitoring abnormal combustion, it prevents engine damage and maintains reliable engine performance. Designed specifically for Honda marine engines, it ensures seamless integration with existing parts, maintaining optimal