Mercury - Cylinder Block & Exhaust Manifold Drain Plug Cooling System Maintenance Plastic Wing-Nut Design 8M0119211. Overview. If you spend any amount of time caring for your MerCruiser engine, you know the small parts often make the biggest difference. A dependable drain plug may not feel glamorous, but when you are winterizing in a cold driveway or draining the block after a long day on the water, having a plug you can trust is everything. That's where the Quicksilver 8M0119211 comes in-a simp