40165-ZY9-010 Engine Side Stopper - Overview. The 40165-ZY9-010 Engine Side Stopper is an essential component in Honda marine engine systems. It plays a crucial role in stabilizing the engine by preventing excessive lateral movement and side impacts, thereby contributing to the overall durability and reliable operation of your outboard motor. Designed specifically for Honda marine engines, this stopper ensures seamless integration with existing parts, maintaining optimal performance and durabili