Honda Spark Plug (D5HS) 98066-55710 - Overview. The Honda Spark Plug (D5HS) 98066-55710 is an essential ignition component within the Honda marine engine systems. Serving the ignition system, it plays a vital role in reliably igniting the fuel-air mixture inside the combustion chamber to ensure smooth and efficient engine operation. Manufactured to meet stringent factory specifications, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Feat