539102603 / 102603 PTO Clutch Replacement for Husqvarna ZTH5223A & ZTH5225A | Warner 5218-5
539102603 / 102603 PTO Clutch Replacement for Husqvarna ZTH5223A & ZTH5225A | Warner 5218-5
Overview
This 539102603 PTO clutch replacement is an aftermarket electric clutch for select Husqvarna ZTH commercial zero-turn mowers, including supported ZTH5223A and ZTH5225A applications. It also replaces 102603, 539109580, and 109580 on compatible installations.
The assembly features a 1-1/8-inch crankshaft bore, a single-groove pulley measuring approximately 6-1/8 inches outside diameter, clockwise rotation viewed from the pulley side, and a reverse-mount configuration.
Key Features
- Aftermarket electric PTO clutch replacement for select Husqvarna ZTH applications
- Primary OEM Reference: Husqvarna 539102603
- Additional OEM References: 102603, 539109580, 109580
- Crankshaft Bore: 1-1/8 inches / 1.125 inches
- Measured Pulley Outside Diameter: approximately 6-1/8 inches / 6.125 inches
- Pulley Type: single-groove V-belt pulley
- Belt Width: 5/8-inch belt on supported applications; use the OEM-specified belt for your mower
- Rotation: clockwise (CW), viewed from the pulley side
- Mounting Style: reverse mount
- Voltage: 12V DC
- Connector: flat side-by-side at clutch or optional wire harness to extend to T-plug
- Integrated electromagnetic clutch and brake assembly
Compatible Husqvarna Applications
- Husqvarna ZTH5223A: select applications specifying one of the OEM clutch numbers listed below
- Husqvarna ZTH5225A: select applications specifying one of the OEM clutch numbers listed below
Fitment varies by product number, serial number, and engine configuration. Confirm the number on your original clutch or consult the Husqvarna parts diagram for your exact mower. Do not order by the ZTH series name alone.
OEM Part Number References
- Husqvarna: 539102603, 539109580
- Short-form catalog references: 102603, 109580
Manufacturer Cross-Reference
- Warner Electric: 5218-5
- Warner Electric: 52185
Before You Order
Compare your original clutch with the product photos and confirm:
- The original clutch number matches an application listed above
- The crankshaft requires a 1-1/8-inch bore
- The bore and key arrangement match your original assembly
- The mower uses a single-groove, reverse-mount clutch
- Rotation is CW when viewed from the pulley side
- The belt groove, pulley offset, and mounting height suit your mower
- The wiring connector and anti-rotation connection match the installation
Need help comparing your clutch? Send us your mower model, product number, serial number, original clutch number, and clear photos before ordering.
What’s Included
- Complete aftermarket electric PTO clutch assembly
- Integrated single-groove pulley
- Pre-installed bearing assembly
- Electromagnetic coil and brake assembly
- Flat side-by-side clutch connector
- Optional wire harness extension
Why Buy From PTO Direct USA?
- Fast USA shipping
- Fitment Guarantee
- Fitment support before and after purchase
- Clear product photos for easier clutch identification
- Support for homeowners, commercial operators, and mower repair professionals
FAQ
Does this PTO clutch replace Husqvarna 539102603?
Yes. This aftermarket clutch is offered as a replacement for Husqvarna 539102603 on supported applications. Match your original clutch number and physical configuration before ordering.
Are 102603, 539109580, and 109580 covered by this listing?
Yes. These references are included in this replacement’s Husqvarna application family. Check the original clutch number, connector, and mounting configuration against your mower before purchasing.
Does this fit every Husqvarna ZTH mower?
No. This listing covers select ZTH5223A and ZTH5225A applications using the listed clutch numbers. Other ZTH models and configurations may require a different clutch.
Why do some reference specifications list a 6.3-inch pulley?
Warner lists a 6.31-inch outside diameter for its 5218-5 clutch. The aftermarket unit offered here has a measured outside diameter of approximately 6.125 inches.
Outside diameter and the working diameter where the belt rides are different measurements. For belt speed, the critical measurement is that working diameter—not the outer flange edge. This aftermarket clutch is designed to replace the OEM and manufacturer part numbers listed here.
What bore size does this clutch use?
This clutch has a 1-1/8-inch crankshaft bore, also written as 1.125 inches. Match the bore and key arrangement to your original clutch.
Is this a reverse-mount clutch?
Yes. This replacement uses a reverse-mount configuration. Follow the mounting orientation and spacer arrangement specified for your mower. Product-photo orientation is not an installation diagram.
What connector does this clutch use?
The clutch has a flat side-by-side connector. An optional wire harness extends the connection to a T-plug. Compare your mower’s wiring connection before choosing the configuration.
What belt should I use?
Use the OEM-specified belt for your exact mower and deck configuration. Belt width, length, and profile must suit the complete drive system.
Can PTO Direct USA help confirm fitment?
Yes. We provide fitment support before and after purchase. Email support@ptodirectusa.com with your mower model, product number, serial number, engine information, and original clutch number. Include photos of the clutch label, bore, pulley, connector, and anti-rotation connection.