The Mercury Racing Flo-Torq II Solid Hub Kit is a precision-engineered component designed for high-performance small shafts. Available under Mercury Marine OEM part number 835258K1 and Quicksilver OEM part number 835258Q1, this kit is intended for applications requiring a direct, solid connection between the propeller and a standard 1-inch propeller shaft.
 
It is commonly used with performance-oriented propeller models such as the Mercury Chopper, Cleaver, Lightning ET, Eagle 3, Eagle 4, Buckshot Cleaver 3, Buckshot Cleaver 4, and Pro ET series.
 
Design Purpose and Application
In performance boating, especially in racing or high-speed recreational applications, maintaining an efficient transfer of torque from the engine to the water is critical. Standard rubber hub systems are designed to absorb vibration and protect the drivetrain from sudden load changes, but this cushioning effect can result in power loss under extreme conditions.
 
The Flo-Torq II Solid Hub Kit replaces that flexible interface with a solid connection, eliminating slippage and ensuring that torque delivery remains consistent, even at high RPMs.
 
This kit is particularly suited to lightweight, high-speed boats where rapid acceleration and precise handling are essential. It is also compatible with propellers used in competitive racing, offshore performance boating, and high-speed bass fishing, where maintaining propeller grip on the shaft under heavy load is a priority.
 
Engineering and Construction
The kit features a splined propeller shaft adapter, precision-machined to interface securely with a 1-inch propeller shaft. A solid aluminum sleeve transmits torque directly to the propeller without flex or give, providing an immediate response to throttle input.
 
The thrust washer is engineered to distribute axial loads evenly across the propeller hub, protecting the lower unit from excessive wear. A heavy-duty propeller nut and locking tab washer secure the assembly, ensuring that the connection remains stable during high-speed operation.
 
Materials were selected for durability in demanding marine environments, with corrosion resistance factored into both the metallic components and the protective coatings applied during manufacturing. The kit is assembled in the United States using a combination of domestic and imported components, meeting Mercury Marine’s OEM standards for fit and performance.
 
Installation Considerations
Before installation, both the propeller and propeller shaft should be inspected and cleaned to remove any debris or corrosion that could interfere with the fit. The splines should be checked for wear, as a solid hub transmits greater mechanical load than a flexible rubber insert. The propeller nut must be torqued to manufacturer specifications, and the locking tab washer should be bent into place to prevent loosening during operation.
 
Due to its rigid coupling, this hub design transmits more vibration to the drivetrain compared to a standard Flo-Torq II rubber hub insert. While this is acceptable—and even advantageous—in racing applications, it may not be suitable for operators seeking a smoother ride in casual cruising conditions.
 
Performance Characteristics
Once installed, the Flo-Torq 2 Solid Hub Kit eliminates the potential slop of a cushioned or worn Delrin Thermoplastic hub system. The propeller responds more immediately to throttle input, which can reduce acceleration times and improve hole shot performance.
 
The lack of torsional give also enhances handling precision during high-speed turns and rapid throttle transitions. This makes the system particularly effective in drag racing, closed-course competition, and offshore performance environments.
 
Summary
The Mercury Racing Flo-Torq II Solid Hub Kit—OEM part numbers 835258K1 and 835258Q1—is a specialized marine propulsion component engineered for applications where maximum torque transfer and reliability are required.
 
Designed for compatibility with select high-performance propellers, it provides a direct mechanical connection between propeller and shaft, ensuring consistent power delivery in the most demanding boating environments.
 
Contact Mike Hill at +1-714-697-1716 or email mike@buckshotracing77.com for technical support.