The Husqvarna 125B is a professional-grade leaf blower designed for demanding residential and commercial use. This parts manual provides detailed diagrams, part numbers, and ordering information for all components of the Husqvarna 125B backpack blower, including the engine assembly, fan housing, throttle controls, harness system, fuel system, and muffler. Use this guide for identification, maintenance, and replacement of genuine Husqvarna parts to ensure optimal performance and safety.
This manual is intended for authorized service technicians and users performing their own maintenance. Always prioritize safety.
| Safety Symbol | Meaning |
|---|---|
| WARNING! | Indicates a potentially hazardous situation which, if not avoided, could result in serious injury or death. |
| CAUTION! | Indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury or product damage. |
| NOTE | Provides helpful information and tips for proper operation and maintenance. |
WARNING! Always disconnect the spark plug boot before performing any maintenance or parts replacement. Use only genuine Husqvarna replacement parts.
Refer to the corresponding figure number for each assembly diagram. Parts are listed in the order of assembly.
NOTE: The part number is essential for ordering. Verify the number against the specific model 125B.
Core power unit components.
| Ref. No. | Part Number | Description | Qty |
|---|---|---|---|
| 1 | 537 27 41-01 | Cylinder Complete | 1 |
| 2 | 537 27 42-01 | Piston Assembly | 1 |
| 3 | 501 84 29-01 | Crankshaft | 1 |
| 4 | 537 27 43-01 | Connecting Rod | 1 |
| 5 | 544 11 34-01 | Spark Plug (Bosch WSR6F) | 1 |
| 6 | 501 84 28-01 | Ignition Module | 1 |
CAUTION! When replacing piston or cylinder, always replace piston rings and circlips. Ensure proper ring gap orientation.
Components responsible for generating airflow.
| Ref. No. | Part Number | Description | Qty |
|---|---|---|---|
| 7 | 544 11 35-01 | Fan Housing Upper | 1 |
| 8 | 544 11 36-01 | Fan Housing Lower | 1 |
| 9 | 537 27 44-01 | Impeller (Fan) | 1 |
| 10 | 501 84 30-01 | Impeller Nut | 1 |
| 11 | 544 11 37-01 | Starter Assembly (Recoil) | 1 |
| 12 | 501 84 31-01 | Starter Rope | 1 |
NOTE: Inspect the impeller for cracks or damage regularly. A damaged impeller can cause imbalance and vibration.
Backpack frame and comfort system.
CAUTION! Check all straps and buckles for wear before each use. A failing harness can lead to loss of control.
Operational control components.
| Ref. No. | Part Number | Description | Qty |
|---|---|---|---|
| 13 | 544 11 42-01 | Throttle Control Lever | 1 |
| 14 | 501 84 33-01 | Throttle Cable | 1 |
| 15 | 544 11 43-01 | Right Handle Grip | 1 |
| 16 | 544 11 44-01 | Left Handle Grip | 1 |
| 17 | 501 84 34-01 | Stop Switch | 1 |
| 18 | 544 11 45-01 | Throttle Lock Lever | 1 |
NOTE: Lubricate throttle cable periodically with a light oil to ensure smooth operation.
Components for fuel delivery and filtration.
WARNING! Always work in a well-ventilated area away from sparks or flames when servicing the fuel system.
Exhaust system components.
CAUTION! The muffler becomes extremely hot during and after operation. Allow the engine to cool completely before touching.
Recommended service intervals for optimal performance and longevity.
| Component | Daily/Before Use | Every 25 Hours | Every 50 Hours | Every 100 Hours/Season |
|---|---|---|---|---|
| Air Filter | Check/clean | Clean | - | Replace |
| Fuel Filter | - | - | Check | Replace |
| Spark Plug | - | Check/clean gap | - | Replace |
| Spark Arrestor | - | - | Clean | Replace if damaged |
| Impeller | Visual check | - | Inspect for damage | - |
| Harness/Straps | Inspect | - | - | Replace if worn |
| Carburetor | - | - | - | Service/Adjust |
Always provide the model number (125B) and the correct part number when ordering.
NOTE: Part numbers are subject to change. Verify the latest part numbers with your dealer or the Husqvarna website.