30520-58G-013 Plug Top Coil Assembly - Overview. The 30520-58G-013 Plug Top Coil Assembly is a critical ignition component designed for Honda marine engine systems. It plays a vital role by providing the electrical spark necessary to ignite the fuel mixture, ensuring reliable operation of your Honda marine engine. Engineered to meet exact OEM specifications, this coil assembly guarantees seamless integration with existing parts, maintaining optimal performance and durability in demanding marine