Mercury - 10W-30 4-Stroke Oil Change Kit Maintenance & Care Marine-Grade Components 8M0188357. Overview. There's a certain kind of peace that comes from taking care of your engine yourself. You know the feeling - the boat's on the trailer or tied gently at the dock, the sun's dipping low, and you're giving your outboard the kind of attention that keeps it running strong all season. An oil change isn't glamorous, but it's one of those rituals that keeps you connected to your engine and confident