31908-ZZ3-003 S/Plg (Lmar6C-9) - Overview. The 31908-ZZ3-003 S/Plg (Lmar6C-9) is a genuine Honda spark plug designed for Honda marine engine systems. This spark plug serves the vital function of igniting the fuel-air mixture within the combustion chamber, ensuring smooth engine start-up and efficient performance. Its precise construction matches factory specifications and tolerances, providing seamless integration with existing parts, maintaining optimal performance and durability.. Key Features