Mercury - Quicksilver 835257K6 Flo-Torq II Propeller Hub Kit High-Performance Mercury & Mariner Outboards & MerCruiser Sterndrives 835257K6. Overview. For serious performance boaters running big power and surface-piercing props, the Quicksilver 835257K6 Flo-Torq II Hub Kit delivers the strength and protection you need. Designed for high-performance Mercury and Mariner outboards and MerCruiser Alpha One and Bravo One sterndrives, it's built to handle aggressive prop setups like the Fury, Tempest