This manual provides comprehensive repair and maintenance information for STIHL chainsaws. It covers safety precautions, troubleshooting common issues, step-by-step repair procedures for engine, fuel system, ignition, chain, and bar components, along with specifications, torque values, and exploded diagrams. Below are key sections for safety, maintenance schedules, troubleshooting, repair procedures, parts identification, and specifications.
Essential safety guidelines before performing any repair or maintenance on your STIHL chainsaw.
| Precaution | Description |
|---|---|
| Disconnect Spark Plug | Always disconnect the spark plug wire before working to prevent accidental starting. |
| Use Proper Tools | Use STIHL-approved tools or equivalents to avoid damage and ensure safety. |
| Work in Ventilated Area | Perform repairs in a well-ventilated space away from sparks or open flames. |
| Wear Protective Gear | Wear safety glasses, gloves, and appropriate clothing. |
| Secure Chainsaw | Clamp the saw securely in a vise or on a stable surface before disassembly. |
| Handle Fuel Safely | Drain fuel tank before repairs; avoid spilling fuel on hot components. |
| Chain Tension | Ensure chain is properly tensioned and sharpened to prevent kickback. |
| Follow Manual Instructions | Adhere strictly to the procedures outlined in this manual. |
Regular maintenance intervals to keep your STIHL chainsaw in optimal working condition.
WARNING! Failure to follow maintenance schedule may result in premature wear, unsafe operation, or voiding of warranty.
Common problems, their likely causes, and corrective actions for STIHL chainsaws.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Engine won't start | Empty fuel tank, clogged fuel filter, faulty spark plug, flooded engine | Refill with fresh fuel mix; replace fuel filter; check/replace spark plug; wait 10 mins then restart with choke off. |
| Engine starts then dies | Dirty air filter, carburetor adjustment, faulty fuel line | Clean/replace air filter; adjust carburetor (H/L screws); inspect fuel lines for leaks/cracks. |
| Chain won't turn | Clutch issues, drive sprocket worn, chain brake engaged | Inspect clutch springs and shoes; replace worn sprocket; disengage chain brake. |
| Excessive vibration | Loose components, unbalanced chain, worn anti-vibration mounts | Tighten all nuts/bolts; balance chain; replace anti-vibration elements. |
| Chain oil not flowing | Empty oil tank, clogged oil passages, faulty oil pump | Refill oil tank; clean oil passages and filter; inspect/replace oil pump. |
| Overheating | Dirty cooling fins, lean fuel mixture, improper carburetor setting | Clean cooling fins; adjust carburetor to richer setting; check fuel mix ratio (50:1). |
Step-by-step procedures for engine disassembly, inspection, and reassembly.
CAUTION! Label all parts during disassembly. Use a torque wrench for reassembly to avoid damage.
Maintenance and repair of fuel tank, lines, filter, and carburetor.
Tip: Always use fresh fuel mix (50:1 with STIHL HP Ultra oil) to prevent carburetor issues.
Proper care for cutting chain, guide bar, and sprocket.
WARNING! Always wear cut-resistant gloves when handling chain. A dull chain increases kickback risk.
Testing and replacing ignition components.
| Component | Test Procedure | Specification |
|---|---|---|
| Spark Plug | Check electrode gap (0.5mm); replace if fouled or cracked. | NGK BPMR7A or equivalent |
| Ignition Coil | Measure primary resistance (0.5-2.0 Ω); secondary (5-15 kΩ). | Replace if out of spec |
| Stop Switch | Check continuity; should be open when off, closed when on. | Replace if faulty |
| Flywheel | Inspect for cracks; check keyway; clean magnets. | Torque nut to 40 Nm |
Note: Use a multimeter for accurate electrical testing. Ensure all connections are clean and tight.
Identification of major components and assembly diagrams.
Reference: Use STIHL part numbers when ordering replacements. Diagrams available in full manual PDF.
Technical data for common STIHL chainsaw models (e.g., MS 170, MS 250, MS 361).
| Model | Displacement | Power Output | Weight | Bar Length |
|---|---|---|---|---|
| MS 170 | 30.1 cc | 1.5 kW / 2.0 hp | 3.9 kg | 12-16" |
| MS 250 | 45.4 cc | 2.3 kW / 3.1 hp | 5.0 kg | 16-18" |
| MS 361 | 59.0 cc | 3.4 kW / 4.6 hp | 6.2 kg | 18-25" |
Additional Specs: Fuel tank capacity: 0.25-0.5 L; Oil tank: 0.2-0.3 L; Chain pitch: 3/8" or .325"; Spark plug gap: 0.5 mm.
Critical torque specifications for safe reassembly (values in Newton-meters, Nm).
CAUTION! Overtightening can strip threads; undertightening can cause parts to loosen during operation.
STIHL limited warranty information and customer support resources.
STIHL offers a limited warranty on materials and workmanship. Warranty period varies by region and model. Keep your purchase receipt and register your product online. For technical support, genuine parts, or to locate a STIHL servicing dealer:
Disclaimer: This manual is for informational purposes. Repairs should be performed by qualified technicians. STIHL is a registered trademark. Always refer to the official manual for your specific model.