917-05121 PTO Clutch Replacement for Troy-Bilt, Cub Cadet, Craftsman | Replaces 717-05121

Overview

This Troy-Bilt PTO clutch 917-05121 replacement also replaces OEM part number 717-05121 and additional part numbers 717-04376, 717-04376A, 917-04376, and 917-04376A. Designed for an exact OEM-spec fit on Troy-Bilt, Cub Cadet, and Craftsman lawn tractors and zero-turn mower platforms, this electric PTO clutch restores smooth blade engagement, consistent torque transfer, and reliable long-term mowing performance.

Commonly used on MTD-built 42-inch zero-turn and lawn tractor platforms, this clutch provides dependable PTO engagement for residential and light commercial mowing applications.

Built with a 6.00-inch pulley diameter, 1-inch crankshaft bore, and CCW rotation, this clutch is engineered for reliable operation at engine speeds up to 3600 RPM. A 370°F thermal cutoff, high-temperature bearings, and an encapsulated electromagnetic coil help protect the assembly from heat, wear, and demanding mowing conditions.

Key Features

• Direct OEM replacement electric PTO clutch assembly
• Pulley Diameter: 6.00 inches
• Crankshaft Size: 1 inch
• Rotation: CCW (counter-clockwise)
• Operating Speed: Up to 3600 RPM
• 370°F thermal cutoff helps prevent overheating damage
• Encapsulated electromagnetic coil for reliable engagement
• High-temperature bearings for consistent performance
• Designed for stable operation under load
• Fully assembled and ready to install

Compatible With These Brands & Model Series

This PTO clutch fits MTD-built mower platforms using the same OEM specification.

• Cub Cadet RZT Series: RZT-42, RZT-S42
• Troy-Bilt Zero-Turns: Colt XP, Mustang Colt
• Craftsman ZTL Series: ZTL7000
• MTD / White Outdoor / Yard-Man / Columbia / MTD Gold: ZT-4200, RZT-42 and similar 42" platforms

Fitment can vary by configuration and production year. Always confirm your part number matches one of the numbers listed below.

Replaces OEM Part Numbers

• MTD / Cub Cadet / Troy-Bilt / Craftsman: 917-05121, 717-05121, 717-04376, 717-04376A, 917-04376, 917-04376A

Aftermarket Cross-Reference Numbers

• Warner: 5217-34, 521744, 5217-77, 5217-90
• STENS: 255-821X

What’s Included

• Complete electric PTO clutch assembly
• Factory-balanced 6.00" pulley
• Pre-installed high-temperature bearings
• Encapsulated electromagnetic coil
• Plug-and-play wiring connector

Why Buy From PTO Direct USA?

• Fast USA shipping
• OEM-spec fitment guarantee
• 1-year warranty
• Premium PTO Direct USA product images for easy identification
• Trusted replacement supplier for homeowners and professionals

Need a different fitment? Browse the full electric PTO clutch catalog to see all available replacement options.