Mercury - Tow N Stow Outboard Cover 175-225 Horsepower FourStroke Series Polysoft II Fabric 8M0221495. Overview. There's a moment after every good day on the water when you look back at your engine-sun setting, deck quiet, the boat rocking gently-and you want to know it's protected until the next adventure. A dependable engine cover gives you that sense of calm. You slide it over the cowling, tighten it down, and suddenly the motor feels sheltered from the sun, the wind, the road, and everything