31914-Z8Y-003 Spark Plug (LR4C-E) - Overview. The 31914-Z8Y-003 spark plug (LR4C-E) is a genuine Honda OEM component designed to support the ignition system of Honda marine engines. Its essential function is to ignite the fuel-air mixture in the cylinders, ensuring smooth and reliable engine performance. As a vital part of the engine's combustion system, this spark plug plays a key role in maintaining engine power and efficiency. Meeting strict factory standards, it ensures seamless integration