The Billet Prop Shaft Bearing Carrier is purpose-built for Mercury Racing 2.4, 2.5, 3.0, and 3.2 liter outboards equipped with Sportmaster and CLE gearcases from Buckshot Racing #77 replaces the Mercury OEM Part (848840T1, 848840A1). The bearing carrier supports both the 1.00-inch standard prop shaft with 15 splines and the 1.25-inch fat shaft with 19 splines.
 
Machined from 6061-T6 billet aluminum rather than cast, it delivers higher structural rigidity, more precise shaft alignment, and better vibration control at the extreme RPM and thrust loads common to competition and high-speed recreational use.
 
Standard and Fat Shaft Systems
Mercury Racing Sportmaster gearcases exist in two primary shaft configurations. The earlier configuration is the 1.00-inch, 15-spline standard shaft that served well in moderate load scenarios but reached its limits under elevated torsional stress.
 
The later 1.25-inch, 19-spline fat shaft increases diameter and spline engagement to spread load more effectively, improving durability during hard launches and sustained top-end runs. The Buckshot Racing #77 Mercury Racing Sportmaster prop shaft carrier is dimensioned to support either configuration, allowing straightforward fitment across mixed fleets and upgrade paths without changing the carrier architecture.
 
Engine and Gearcase Compatibility
Our bearing carrier is engineered for Sportmaster and CLE gearcases found on the Mercury Racing engines in the 2.4, 2.5, 3.0, and 3.2 liter outbaords. Typical applications include 225 ProMax, 245 Carb, 260 EFI, 280 ROS, 300 Drag, and 300 XS EFI models, along with the 200XS ROS Optimax, 150, 200, 225 Pro Max, and Mariner 150, 200, 225 Super Mag when configured with the 1.25-inch fat shaft.
 
The carrier is a direct replacement for OEM assemblies identified as 847610, 847610A1, 848840, 848840A1, and 848840T1, providing an immediate upgrade from a cast housing to a billet unit without altering external fit.
 
Technical Design and Construction
The Mercury Racing Sportmaster bearing carrier from Buckshot Racing is CNC-machined from 6061-T6 billet to tight tolerances that maintain concentricity between bearing bores and seal lands.
 
The billet construction resists distortion from thrust loading and thermal cycling better than cast housings, which helps the bearing maintain true running geometry at high shaft speeds.
 
Reduced housing flex translates to lower vibration, cleaner gear tooth contact, and improved sealing performance over longer service intervals. These traits are particularly valuable in drag racing, endurance events, and high-speed lake running where gearcases operate at the limits of hydrodynamic loading.
 
Bearing and Seal Interface
Serviceability remains OEM-compatible. The carrier accepts the 31-817072 roller bearing and oil seals such as the 26-815565 standard seal or the tapered 31-48939A2, allowing the use of readily available Mercury components.
 
Because bearing alignment determines longevity, the assemblies must be pressed with appropriate drivers and supported on the correct datum surfaces to avoid cocking the bearing or damaging the seal lands. Proper lubrication during assembly and verification of preload and end-play are essential to achieve the intended durability gains.
 
Performance Outcomes
When installed correctly, the Buckshot Racing #77 Mercury Racing Sportmaster prop shaft bearing carrier improves drivetrain stability at elevated RPM, reduces vibration-related wear on gears and seals, and increases thrust load capacity during hard acceleration.
 
The net effect is smoother operation, longer service life, and greater reliability in demanding environments. Users transitioning from a cast carrier typically see reduced maintenance frequency and more consistent performance during long, high-speed runs.
 
Installation and Service Notes
Only the billet carrier housing is supplied. Bearings, seals, and fasteners are available separately from Buckshot Racing #77 for your specific gearcase and shaft configuration.
 
Installation requires a proper seal kit, bearing press tooling, careful alignment procedures, and confirmation of fitment before operation. Attention to these details ensures the carrier delivers the expected strength and sealing performance.
 
For racers and performance enthusiasts seeking a durable, precisely machined upgrade, purchasing through Buckshot Racing ensures correct application and technical assistance.
 
Our carrier provides a robust, precisely machined replacement for cast OEM carriers in Sportmaster and CLE gearcases. Its compatibility with both 1.00-inch and 1.25-inch shafts, combined with the stiffness and alignment stability of 6061-T6 billet construction, makes it a reliable foundation for high-RPM, high-thrust applications across Mercury Racing 2.4, 2.5, 3.0, and 3.2 liter platforms.
 
Includes one (1) Billet Carrier, Big Propshaft Bearing (bearings or seals are sold separately)
 
For technical support, contact Mike Hill at +1-714-697-1716 or mike@buckshotracing77.com