The 1.62 Right-Hand (RH) Gear Set Kit for Mercury Sportmaster and Torquemaster from Buckshot Racing #77 is a precision-engineered replacement for Mercury OEM part number 859321T05.
Designed for Mercury Racing 3.0L and 3.2L Sportmaster gearcases and Torquemaster lower units, this gear set is built to deliver exceptional durability, efficient power transfer, and consistent high-performance operation under extreme load and elevated RPM conditions. It is purpose-built for performance boating enthusiasts and professionals who demand reliability in high-stress marine environments.
Featuring a 1.62:1 gear ratio, the 1.62 Right-Hand (RH) Gear Set Kit offers a performance-focused balance that favors increased top-end speed while maintaining strong mid-range acceleration. This ratio is ideal for high-performance outboard applications where maximizing speed and maintaining efficient power delivery at higher RPM ranges is critical.
The optimized gear ratio improves propeller efficiency and enhances overall drivetrain performance, making it well-suited for racing, high-speed recreational boating, and competitive offshore use.
Manufactured from heat-treated, high-strength alloy steel, the 1.62 RH Gear Set Kit for Mercury Sportmaster and Torquemaster is engineered to withstand the extreme mechanical stresses associated with aggressive boating conditions. Each gear is CNC-machined to tight, aerospace-grade tolerances to ensure precise meshing, reduced vibration, and long-term reliability.
A micro-polished finish minimizes friction and heat buildup, resulting in smoother operation, reduced wear, and extended service life—even during prolonged high-speed runs and heavy-load applications.
As a direct replacement for Mercury OEM part 859321T05, this gear set kit installs cleanly into compatible 3.0L and 3.2L Sportmaster and Torquemaster lower units without requiring modifications. While installation is straightforward, professional setup is recommended to ensure proper gear lash, bearing preload, and shaft alignment for optimal performance and longevity. Please note that prop shaft seals for 1.25-inch diameter shafts are not included and must be sourced separately based on your specific application.
This gear set kit is compatible with a wide range of Mercury Racing outboard engines equipped with Sportmaster or Torquemaster gearcases. Supported models include the 225 HP Pro XS (3.0L), 250 HP Pro XS (3.0L), 250 HP XS (3.0L), 250 HP Sport XS (3.0L), 300 HP XS (3.2L), and the 300X EFI PRO MAX (3.0L). These engines benefit from the increased speed potential, precision engineering, and durability provided by the 1.62 gear ratio configuration.
The 1.62 Right-Hand (RH) Gear Set Kit for Mercury Sportmaster and Torquemaster from Buckshot Racing #77 is the result of extensive testing and real-world validation in demanding marine environments. Its advanced materials, precision machining, and performance-oriented design make it an ideal solution for rebuilding or upgrading high-performance Mercury Racing gearcases.
Whether you’re pushing for higher top-end speed or reinforcing your drivetrain for competitive use, this gear set provides a dependable and high-performance foundation.