Mercury - Ignition Coil MerCruiser MPI Series Marine-Grade Composite 8M0054588. Overview. There's a certain comfort that comes from turning the key and hearing your MerCruiser fire instantly-no hesitation, no uneven stumble, just smooth, confident ignition. Out on the water, that moment matters. It means you can focus on the run ahead instead of worrying about what's happening under the engine hatch. The Quicksilver 8M0054588 Ignition Coil is one of those quiet, crucial parts that keeps your day