Mercury - Spark Plug V12 Verado & SeaPro Series Precision-Engineered Metal Core Priced Individually 8M0180173. Overview. When you run a Mercury V12, you're counting on an engine that answers instantly whether you're easing out of the marina at sunrise or pushing hard through a rolling offshore swell. There's a quiet confidence that comes from knowing every ignition cycle fires clean, steady, and strong. These Mercury Marine spark plugs deliver that feeling. They bring a sense of trust you can li