Mercury - Premium Plus 2-Stroke Marine Engine Oil Synthetic Blend 858028K01. Overview. There is a moment when you turn the key, hear that low rumble, and know your day on the water's about to begin. That sound-steady, confident, alive-is what Mercury Premium Plus 2-Stroke Marine Engine Oil helps protect. This oil isn't just another maintenance item; it's the quiet reassurance that your engine's ready for anything. Whether you're pushing through chop, cruising a calm river, or running wide open f