12166-ZZ3-030 Engine Side Stopper - Overview. The 12166-ZZ3-030 Engine Side Stopper is a vital component in Honda marine engine systems. It functions within the engine assembly as a physical barrier or support, helping to limit the movement of engine parts and preventing damage due to over-extension or impact. This stopper is designed to maintain the mechanical integrity of the engine, ensuring reliable and seamless operation under demanding marine conditions. Crafted to meet exact factory speci