Mercury - Bravo One 300-Hour Maintenance Kit MerCruiser Sterndrive Service Complete Marine Components 8M0215915. Overview. Anyone who runs a MerCruiser Bravo One sterndrive knows that smooth days on the water start with dependable maintenance. There's a certain peace that comes from servicing your drive the right way-no guessing, no missing pieces, no "I'll get to that later." This 300-hour maintenance kit delivers that confidence. Everything you need shows up in one box, organized, matched, and