Mercury - Prop Nut, Front V12 Contra-Rotating Prop System Brass 8M0176914. Overview. When you run a V12 outboard, you expect everything behind the transom to feel rock solid. There's a certain confidence that comes from knowing each part - even the small ones you rarely see - is built to handle serious water and serious power. The Mercury Prop Nut 8M0176914 is one of those pieces. It's not flashy, but it quietly holds the heart of your propulsion system together, keeping both props working in pe