The Stihl FS 85 is a professional-grade brushcutter/trimmer designed for demanding vegetation management. This parts manual provides detailed diagrams, part numbers, and ordering information for the FS 85's engine assembly, cutting head, drive shaft, handle assembly, and fuel system. Below are key sections for identification, engine parts, cutting attachments, drive system, handle & controls, fuel system, maintenance parts, and ordering.
Locate the model number (FS 85) and serial number on the machine housing. Use only genuine Stihl parts for repair to ensure safety and performance.
| Component | Identification |
|---|---|
| Model Plate | Located on the engine housing or rear handle |
| Engine Type | 2-stroke, single-cylinder, air-cooled |
| Displacement | 27.2 cc (1.7 cu. in.) |
| Powerhead | FS 85 specific; not interchangeable with other series |
| Safety Symbols | Refer to decals on machine for operational warnings |
WARNING! Always disconnect the spark plug boot before performing any parts replacement or maintenance.
Cylinder, piston, crankshaft, crankcase, and associated components.
Note: Engine parts are precision matched; replace in sets as recommended.
Parts for trimmer heads, blades, and blade adapters.
CAUTION! Ensure the machine is stopped and the spark plug is disconnected before changing cutting attachments.
Handlebar, throttle trigger, throttle cable, lockout lever, and harness attachments.
Handle Assembly: D-shaped or loop handle options. Includes vibration dampeners.
Throttle Control: Throttle trigger, cable, and carburetor linkage. Master Control Lever: Combines stop switch and choke functions. Harness Hooks: Attachment points for shoulder harness.
Fuel tank, cap, filter, lines, and carburetor components.
Tip: Replace fuel lines and filter annually to prevent running issues.
Supports engine breathing and starting systems.
WARNING! Never operate the machine without the air filter installed to avoid engine damage.
Commonly replaced items for routine upkeep.
Spark plug, air filter set, fuel filter, fuel line kit, clutch drum, trimmer line, blade, anti-vibration buffers, and drive shaft coupling.
CAUTION! Use only Stihl-approved 2-stroke engine oil mixed with gasoline as specified.
Refer to official Stihl FS 85 exploded view diagrams for visual part location and assembly order. Diagrams are organized by major assembly groups.
Always provide the full model number (FS 85) and serial number when ordering. Use the part numbers listed in this manual or from the corresponding exploded diagram.
| Part Description | Stihl Part Number Example | Qty per Assembly |
|---|---|---|
| Piston Assembly | XXXX-XXX-XXXX | 1 |
| Air Filter Set | XXXX-XXX-XXXX | 1 |
| Trimmer Head Complete | XXXX-XXX-XXXX | 1 |
| Fuel Line Kit | XXXX-XXX-XXXX | 1 |
| Clutch Shoes Set | XXXX-XXX-XXXX | 3 |
| Symptom | Possible Failed Part | Part to Check/Replace |
|---|---|---|
| Engine won't start | Ignition module, spark plug | Check spark; replace coil or plug. |
| Loss of power | Clutch, fuel filter, piston rings | Inspect clutch shoes; replace fuel filter; check compression. |
| Vibration excessive | Bent drive shaft, worn bearings | Inspect shaft and gearhead bearings. |
| Cutting head doesn't spin | Sheared drive shaft, clutch | Inspect shaft coupling and clutch engagement. |
| Fuel leak | Cracked fuel tank, deteriorated lines | Inspect tank and replace fuel lines. |
Service Note: For complex repairs, consult an authorized Stihl servicing dealer.
Dealer Locator & Support: Visit www.stihlusa.com or contact your local authorized Stihl dealer.