Mercury - Vented Splash Cover for 150hp Pro XS Engines Engine Protection Cover Black Polysoft II Material 8M0228531. Overview. When you run a Mercury 150hp Pro XS, you get used to trusting that engine with your day - the long runs, the choppy afternoons, the calm nights idling back to the ramp. That kind of trust comes from experience, and this vented splash cover fits right into that feeling. It gives you the quiet confidence that your engine's finish will stay protected no matter what the wind