Mercury - MerCruiser 6.2L MPI 300 Hour Maintenance Kit Precision Service Kit Marine-Ready Components 8M0147070. Overview. There's a certain peace you feel when you know your engine is cared for the right way. When you hit the throttle and everything hums exactly as it should, it reminds you why good maintenance matters out on open water. The Mercury Marine part number 8M0147070, a complete 300-hour maintenance kit for MerCruiser 6.2L MPI engines with Bravo sterndrives, gives you that confidence