Exmark Lazer Z PTO Clutch Quick Reference
Classic Exmark Lazer Z mowers do not all use the same electric PTO clutch. The correct clutch can change with the mower’s engine package, serial number, crankshaft diameter, and original Exmark clutch number.
The three common clutch paths covered in this guide are:
- 103-0662 path: select 23 hp machines using a 1-inch crankshaft bore
- 103-0664 path: select early 25 hp machines using a 1-1/8-inch crankshaft bore
- 103-0665 path: select later 25 and 26 hp machines using a 1-1/8-inch crankshaft bore
Do not choose a clutch from the Lazer Z name or serial number alone. Exmark parts diagrams show different clutch numbers for different engine packages within the same broader mower generation.
Quick Exmark Lazer Z PTO Clutch Routing
| Common Application Path | Primary Exmark Number | Earlier Exmark Numbers | Warner Path | Bore | Torque | Product Route |
|---|---|---|---|---|---|---|
| Select 23 hp Lazer Z configurations | 103-0662 | 103-0661, 103-0500, 1-631644, 1-631731 | 5218-76 | 1 inch | 200 ft-lbs | View 103-0662 PTO Clutch |
| Common early 25 hp path, frequently cataloged through serial 159999 | 103-0664 | 1-631645, 1-633099 | 5218-5 | 1-1/8 inch | 175 ft-lbs | View 1-631645 / 103-0664 PTO Clutch |
| Select later 25 and 26 hp path, frequently cataloged within serial 160000–369999 | 103-0665 | 103-0501, 1-631732, 1-641300 | 5218-213 Earlier 5218-65 | 1-1/8 inch | 200 ft-lbs | View 103-0665 PTO Clutch |
Routing rule: Match the original Exmark clutch number first. Then confirm the engine, complete serial number, crankshaft bore, pulley diameter, connector, mounting orientation, and pulley offset.
103-0662 PTO Clutch Path
The 103-0662 path is used on select Exmark Lazer Z machines with a 1-inch engine crankshaft. Exmark parts documentation identifies this clutch on select 23 hp engine configurations.
View the 103-0662 PTO clutch replacement.
103-0662 Reference Numbers
- Primary Exmark Number: 103-0662
- Earlier Exmark Numbers: 103-0660, 103-0661, 103-0500
- Additional Exmark Numbers: 1-631644, 1-631731, 1-633098, 1-641213
- Warner Reference: 5218-76
103-0662 Reference Specifications
- Voltage: 12 VDC
- Rated Torque: 200 ft-lbs
- Crankshaft Bore: 1 inch with standard keyway
- Pulley Diameter: approximately 6.31 inch
- Rotation: CW from pulley side
- Mounting Style: reverse mount
- Connection Type: integral electrical connection
Important: This is not the same bore size as 103-0664 or 103-0665. A 1-inch clutch will not fit a 1-1/8-inch crankshaft, and a 1-1/8-inch clutch will be loose on a 1-inch crankshaft.
103-0664 / 1-631645 PTO Clutch Path
The 103-0664 path is commonly associated with select early 25 hp Exmark Lazer Z applications, frequently cataloged for serial numbers through 159999.
View the 1-631645 / 103-0664 PTO clutch replacement.
103-0664 Reference Numbers
- Primary Exmark Number: 103-0664
- Earlier Exmark Numbers: 1-631645, 631645
- Additional Exmark Numbers: 1-633099, 633099, E633099
- Warner Reference: 5218-5
103-0664 Reference Specifications
- Voltage: 12 VDC
- Rated Torque: 175 ft-lbs
- Crankshaft Bore: 1-1/8 inch with standard keyway
- Pulley Diameter: approximately 6.31 inch
- Rotation: CW from pulley side
- Mounting Style: reverse mount
- Connection Type: integral electrical connection
Serial-range warning: Serial 159999 and lower is a useful catalog route for the early 25 hp clutch path, but it is not a substitute for checking the engine and original clutch number. Lower-horsepower machines may use the separate 1-inch 103-0662 path.
103-0665 / 1-631732 PTO Clutch Path
The 103-0665 path is used on select later Exmark Lazer Z machines with 25 and 26 hp engine packages. Established replacement data commonly associates this path with select serial 160000–369999 applications.
View the 103-0665 PTO clutch replacement.
103-0665 Reference Numbers
- Primary Exmark Number: 103-0665
- Earlier Exmark Number: 103-0501
- Additional Exmark Numbers: 1-631732, 631732, E631732
- Additional Exmark Number: 1-641300, 641300
- Warner Reference: 5218-213
- Earlier Warner Number: 5218-65
103-0665 Reference Specifications
- Voltage: 12 VDC
- Rated Torque: 200 ft-lbs
- Crankshaft Bore: 1-1/8 inch with standard keyway
- Pulley Diameter: approximately 6.31 inch
- Rotation: CW from pulley side
- Mounting Style: reverse mount
- Connection Type: integral electrical connection
Engine-package warning: A serial number inside the commonly published 160000–369999 range does not automatically confirm 103-0665. Exmark used the separate 103-0662 clutch on certain 23 hp configurations within the broader classic Lazer Z family.
103-0664 vs. 103-0665
The early 103-0664 and later 103-0665 paths share several major physical specifications, but they should remain separate part-number routes.
| Specification | 103-0664 / 1-631645 | 103-0665 / 1-631732 |
|---|---|---|
| Common Engine Path | Select early 25 hp | Select later 25 and 26 hp |
| Common Serial Routing | Frequently listed through 159999 | Frequently listed within 160000–369999 |
| Warner Reference | 5218-5 | 5218-213 |
| Rated Torque | 175 ft-lbs | 200 ft-lbs |
| Crankshaft Bore | 1-1/8 inch keyed | 1-1/8 inch keyed |
| Pulley Diameter | Approximately 6.31 inch | Approximately 6.31 inch |
| Rotation | CW from pulley side | CW from pulley side |
| Mounting | Reverse mount | Reverse mount |
| Electrical Connection | Integral | Integral |
Similar dimensions do not prove interchangeability. Match the original Exmark or Warner part number before substituting between these clutch paths.
The 1-Inch vs. 1-1/8-Inch Bore Trap
The most important physical difference in this classic Lazer Z group is the engine crankshaft diameter.
- 103-0662 / Warner 5218-76: 1-inch bore
- 103-0664 / Warner 5218-5: 1-1/8-inch bore
- 103-0665 / Warner 5218-213: 1-1/8-inch bore
Do not estimate the crankshaft size visually. A difference of 1/8 inch is enough to make the clutch completely incompatible.
When the original clutch label is unreadable, measure the engine crankshaft with calipers after safely removing the clutch and cleaning any rust or debris from the shaft.
Why Serial Number Alone Is Not Enough
Serial number is an important Exmark fitment tool, but it does not identify the clutch by itself. Exmark parts documentation can assign different clutch numbers according to engine horsepower and engine configuration within the same mower generation.
Before ordering, confirm all of the following:
- Complete Exmark mower model number
- Complete mower serial number
- Engine manufacturer
- Engine horsepower or exact engine model
- Original Exmark clutch number
- Original Warner number, when readable
- Crankshaft bore diameter
- Pulley diameter and pulley offset
- Rotation viewed from the pulley side
- Electrical connector
- Anti-rotation bracket or clutch-strap arrangement
Use the official Exmark manual and parts-diagram lookup for the complete mower model and serial number before relying on a broad Lazer Z application claim.
Reverse Mount and Rotation
These Warner reference clutches are classified as reverse-mount clutches with CW rotation.
- Reverse mount: describes the clutch’s installation orientation on the engine crankshaft
- CW rotation: describes the operating direction when viewed from the pulley side
Reverse mounting does not change the listed pulley-side rotation. Match both specifications with the original clutch.
How to Confirm the Correct Lazer Z Clutch
Use this order of operations:
- Read the complete number from the original clutch label.
- Look up the mower using the complete Exmark model and serial number.
- Confirm the engine horsepower and engine model.
- Confirm whether the crankshaft is 1 inch or 1-1/8 inch.
- Measure the pulley diameter and compare the pulley offset.
- Compare the electrical connection and wire direction.
- Inspect the anti-rotation strap, bracket, spacers, and surrounding clearance.
Do not order by appearance alone. These clutches can look very similar despite having different bore sizes, torque ratings, OEM numbers, and application paths.
Common Exmark Lazer Z Ordering Mistakes
- Assuming every serial number below 160000 uses 103-0664
- Assuming every serial number above 160000 uses 103-0665
- Ignoring the engine horsepower or engine model
- Confusing the 1-inch 103-0662 clutch with a 1-1/8-inch clutch
- Treating 1-631645 and 1-631732 as the same part number
- Ordering from the Lazer Z name or deck size alone
- Using only the incomplete Warner family number “5218”
- Failing to compare pulley offset and anti-rotation hardware
Need Help Confirming Fitment?
Send PTO Direct USA the complete Exmark mower model, serial number, engine model, engine horsepower, deck size, and original clutch number.
Include clear photos of the mower identification tag, clutch label, keyed bore, pulley, electrical connector, mounting orientation, clutch strap, and anti-rotation hardware.
When the clutch label is unreadable, include measurements for the crankshaft diameter, pulley outside diameter, pulley offset, and overall clutch height.
FAQ
What PTO clutch fits an Exmark Lazer Z?
The correct clutch depends on the model, serial number, and engine package. Common classic Lazer Z paths include 103-0662, 103-0664, and 103-0665.
Does every early Exmark Lazer Z use 1-631645?
No. The 1-631645 / 103-0664 path is commonly associated with select early 25 hp applications. Other early machines may use a different clutch, including the 1-inch 103-0662 path.
Does every Exmark Lazer Z with serial 160000 or higher use 103-0665?
No. Serial number alone is not enough. Exmark used different clutch numbers according to engine package, including a separate 103-0662 clutch on certain 23 hp configurations.
Is Exmark 1-633099 the same path as 1-631645?
Yes. Both numbers are associated with the early 103-0664 / Warner 5218-5 replacement path.
Is Exmark 1-631732 the same as 1-631645?
No. Exmark 1-631732 follows the later 103-0665 / Warner 5218-213 path. Exmark 1-631645 follows the earlier 103-0664 / Warner 5218-5 path.
What Warner clutch crosses to Exmark 103-0664?
The primary Warner cross-reference for Exmark 103-0664, 1-631645, and 1-633099 is Warner 5218-5.
What Warner clutch crosses to Exmark 103-0665?
The primary Warner cross-reference is Warner 5218-213. Warner identifies 5218-213 as the replacement for the earlier 5218-65 clutch.
What Warner clutch crosses to Exmark 103-0662?
The established Warner path is Warner 5218-76.
What bore size does Exmark 103-0662 use?
The 103-0662 / Warner 5218-76 path uses a 1-inch keyed crankshaft bore.
What bore size does Exmark 103-0664 use?
The 103-0664 / Warner 5218-5 path uses a 1-1/8-inch keyed crankshaft bore.
What bore size does Exmark 103-0665 use?
The 103-0665 / Warner 5218-213 path uses a 1-1/8-inch keyed crankshaft bore.
Does reverse mount mean the rotation should be reversed?
No. Reverse mount describes the installation orientation. These clutch paths are still listed as CW rotation when viewed from the pulley side.
Can I order an Exmark Lazer Z clutch by appearance?
No. Match the original clutch number first, then confirm the engine package, serial number, bore, pulley diameter, rotation, connector, pulley offset, and anti-rotation hardware.