Mercury - 300 Hour Maintenance Kit MerCruiser 4.3L MPI Alpha Series OEM Service Components 8M0147064. Overview. There's a certain comfort that comes from knowing your engine is ready for whatever the water throws your way. When you run a MerCruiser 4.3L MPI with an Alpha sterndrive, you expect smooth throttle response, steady cooling, and the kind of reliability that lets you explore a little farther each time. The Mercury 8M0147064 300 Hour Maintenance Kit keeps that trust alive. It's the kit y