603078 PTO Clutch Replacement for Encore Xtreme & Z Series | 1-Inch Bore

Overview

This Encore 603078 PTO clutch replacement is an aftermarket electric clutch for select Encore X-Treme and Z Series zero-turn mowers. Factory application references include specific 52-inch and 60-inch X-Treme models and the 60K25Z Z Series mower.

Built with a 1-inch crankshaft bore, 7.20-inch black pulley and counter-clockwise rotation, this clutch replaces the electric mower deck engagement assembly when the original part number and installation configuration match.

Key Features & Specifications

• Aftermarket replacement for the Encore 603078 clutch application
• Crankshaft Bore: 1 inch / 1.000 inch
• Pulley Diameter: 7.20 inches
• Pulley Finish: Black
• Rotation: CCW, viewed from the pulley side
• Belt Width: 1/2-inch or 5/8-inch belt applications
• Complete clutch assembly with installed bearings and integrated brake
• Electrical Connection: Connector and wiring as shown in the product photos

Compatible Encore Models & Factory References

The following Encore factory references identify 603078 as the electric clutch. Match your complete mower model and original clutch before ordering, especially if the engine or wiring has been changed.

Encore X-Treme — 52-Inch Deck

• 52B25X
• 52K23X
• 52K26X

Encore X-Treme — 60-Inch Deck

• 60B25X
• 60K25X

Encore Z Series — 60-Inch Deck

• 60K25Z

Encore's factory quick-reference manual lists 603078 for 60K25Z on PDF page 30 and for 52B25X, 52K23X, 60B25X and 60K25X on PDF pages 33–36.

For 52K26X, see the factory drive diagram and parts list: printed pages E-1 and E-2, PDF pages 13–14, item 26.

Fitment note: Other Encore configurations use different clutches. Do not extend these references to every X-Treme or Z Series mower.

Replacement & Cross-Reference Numbers

• Encore OEM Reference: 603078
• Aftermarket Catalog Reference: Xtreme X0017 / Stens X0017

Related Toro / Exmark application: Encore 603078 and Toro / Exmark 103-0690 appear in the same aftermarket replacement family. View our dedicated 103-0690 PTO clutch listing for additional Toro and Exmark replacement references.

Cross-reference numbers identify the replacement application. This product is our standard black pulley aftermarket clutch.

Connector & Installation Check

The Encore 52K26X manual lists 603083 separately as a clutch adapter harness. That harness number is not a clutch replacement number. Compare your mower-side plug with our product photos and retain or replace the appropriate adapter as needed.

Follow the mower and clutch installation instructions for the shaft key, spacers, retaining hardware, pulley alignment and anti-rotation restraint. Secure the clutch wiring clear of the belt and moving parts.

What's Included

• One complete electric PTO clutch assembly
• 7.20-inch black pulley, installed bearings and integrated brake
• Electrical connector and wiring as pictured

A separate Encore 603083 adapter harness and installation hardware are included only if expressly shown or specified with the selected product.

Why Buy From PTO Direct USA?

• Fast USA shipping
• Fitment guarantee
• 1-year limited warranty
• Clear product photos for clutch and connector identification
• Fitment support before and after purchase.

FAQ

Does this replace Encore 603078?

Yes, for applications matching the listed clutch number, dimensions, connector and mounting configuration.

Does this fit every 52-inch or 60-inch Encore mower?

No. Confirm the complete model and original clutch number. The factory applications listed above are specific examples.

Is 603078 related to Toro / Exmark 103-0690?

Yes. Aftermarket catalogs group both numbers under X0017. The 103-0690 listing covers the related Toro and Exmark references; this page focuses on Encore.

Will this fit a 1-1/8-inch crankshaft?

No. This clutch requires a 1-inch crankshaft. Confirm the shaft size if the engine has been replaced.

Can you help confirm my clutch?

Contact PTO Direct USA with your mower model, serial number and clear photos of the original clutch label, pulley, connector and mounting arrangement. Email support@ptodirectusa.com or text photos to (541) 361-8778.

Need installation help? Read our PTO clutch installation guide.

Need another application? Browse the full electric PTO clutch catalog.