Mercury - Quicksilver Rotor Assembly Ignition System Component Coated Brass and Polymer 13524T12. Overview. When you run a tow sport boat, your engine doesn't get much of a break. It idles long, jumps hard, and spends its life bouncing between full throttle and steady pulls. The Mercury Marine 13524T12 Quicksilver Rotor Assembly is built for that kind of work. Designed for MerCruiser Black Scorpion engines, it keeps your ignition firing smooth and steady, no matter how hard the load. It's the pa