This Mercury Big Prop Needle Shaft Carrier Bearing (OEM 817072 replacement) is a precision-engineered component designed for high-performance Mercury outboard gearcases, including CLE (Crescent Leading Edge), Sportmaster, and Torqmaster lower units.
 
Built to handle extreme loads and high-RPM operation, this bearing is critical to maintaining prop shaft alignment, gearcase durability, and peak performance in Mercury Racing, Pro Max, and Pro XS outboards.
 
Fits Mercury High-Performance Gearcases & Engines
This bearing is used in Mercury 2.4L CLE gearcases and later 2.5L, 3.0L, and 3.2L Sportmaster and Torqmaster gearcases, supporting a wide range of Mercury high-output outboards.
 
Common Compatible Mercury Engines
This carrier bearing is found in many performance and EFI models, including:
150 Pro Max / Super Mag
200 EFI Pro Max / Super Mag
225 EFI Pro Max / Super Mag
225X EFI Pro Max
250XB (3.0L EFI)
300 Pro Max (3.0L EFI)
300X (3.0L EFI) Pro Max
300 (3.0L EFI) Super Magnum
 
Mercury XS & Pro XS Series, including:
200 HP XS 2.5L V6
225 HP XS 2.5L V6
225 HP Pro XS 3.0L V6
250 HP XS 3.0L V6
250 HP Pro XS 3.0L V6
300 HP XS 3.2L V6
Also includes variants such as:
250 HP Sport XS 2.5L
225 HP Sport XS 2.5L / 3.0L
200 HP XS ROS 2.5L
 
Offshore & EFI Models
2.5L 280 ROS EFI Offshore
2.5L 260 EFI 
250 Long (3.0L EFI)
2.5XS (2.5L)
JP (3.0L)
 
OEM Quality – Manufactured by Koyo JTEKT
This bearing is manufactured by Koyo JTEKT, a global leader in precision bearing technology and an OEM supplier trusted by Mercury Marine.
 
Koyo bearings are used in high-performance automotive and motorsports applications, including Formula 1 and NASCAR, and are known for exceptional durability, tight tolerances, and consistent performance under extreme conditions.
 
Produced in advanced U.S. manufacturing facilities, these bearings meet strict ISO 9001 and TS16949 quality standards, ensuring reliable performance in demanding marine environments.
 
Engineered for High-Speed Mercury Gearcases
Constructed from high-strength alloy steel, this bearing features hardened, precision-ground raceways designed to handle extreme axial and radial loads generated by high-horsepower outboards.
 
The low-friction surface finish reduces heat buildup and improves efficiency at high RPM, while corrosion-resistant properties help protect against saltwater exposure and long-term wear.
Precision manufacturing ensures proper prop shaft alignment, minimizing vibration, reducing gear wear, and maintaining optimal gearcase performance.
 
Installation Notes & Specifications
Proper installation is critical for performance and longevity.
The carrier housing should be thoroughly cleaned before installation, and a light coating of marine-grade anti-seize should be applied to prevent galling.
 
The bearing must be pressed in using a hydraulic press or bearing driver tool, ensuring it seats squarely and evenly.
 
The carrier retaining (spanner) nut should be torqued to 90–110 ft-lbs (122–149 Nm) using the correct tool and a calibrated torque wrench.
 
After assembly, verify prop shaft end play using a dial indicator. Proper end play is typically 0.002–0.004 inches (0.05–0.10 mm) to meet Mercury performance specifications.
 
Replaces Mercury Part Numbers
This needle bearing replaces multiple Mercury OEM part numbers, including:
817072
15265A1
15265A2
23-883478
Always confirm fitment using your Mercury serial number and service manual.
 
Why This Bearing Matters
The prop shaft carrier bearing is critical to gearcase reliability and performance. A worn or damaged bearing can cause:
Prop shaft misalignment
Increased vibration
Premature gear wear
Loss of efficiency and speed
 
Replacing the bearing ensures smooth rotation, proper load support, and long-term durability, especially in high-performance, offshore, and tournament applications.
 
Built for Performance Boating
Whether you're running a Pro Max, 300X, Pro XS, or Mercury Racing outboard, this Mercury big prop shaft carrier bearing delivers the strength, precision, and reliability required for high-speed marine performance.
 
Trusted by performance boaters, racers, and marine technicians, it is an essential component for maintaining Mercury Sportmaster, CLE, and Torqmaster gearcases under extreme conditions.
 
Contact mike@buckshotracing77.com or +1-714-697-1716 with any questions.