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Aug. 19, 2020

Prop Bite: Quiet the Clunk with the Mercury Flo-Torq SSR Propeller Hub Kit

Install the new Mercury Flo-Torq SSR propeller hub kit and enjoy a quieter, smoother boating experience.


If you’ve ever shifted an outboard from neutral to forward or reverse gear, you know the sound and feel of “shift clunk.” It’s the noise created when freeplay in the drivetrain is taken up as the parts in the system engage one another to turn the propeller.

Though shift clunk isn’t damaging to an outboard, no one wants to hear it, which is why Mercury created the Flo-Torq system. Flo-Torq utilizes proven Soft-Shift Rubber technology to virtually eliminate shift clunk by absorbing much of the energy generated when the prop engages. The latest evolution in the Flo-Torq system is the new Flo-Torq SSR prop hub kit, which was designed for use with 40hp to 225hp Mercury outboards with a 1-inch prop shaft for general-purpose, non-surface-piercing applications (where the driver is not trimming excessively high and causing part of the prop to run above the surface).

Flo-Torq SSR is a modular prop hub that provides a cushion between the outboard and the prop. In addition to reducing shift clunk, it also protects the drivetrain from most impacts. If the prop contacts a hard bottom or debris in the water, for instance, the Flo-Torq SSR hub absorbs that shock and gives way, protecting the gearcase components from damage that can be expensive to repair.

Mercury has also updated materials to address the issue of prop rattle, which can occur in some low-speed situations. Flo-Torq SSR is the quietest hub system ever offered by Mercury – up to 23% quieter than Flo-Torq II. Boat owners can install the new Flo-Torq SSR system in most Mercury prop models and enjoy an instant reduction in noise when shifting, as well as some peace of mind on shallow waters.

The Flo-Torq SSR hub system is available now from authorized Mercury Marine dealers who can also offer expert advice on the complete line of Mercury props and other Flo-Torq system options.

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