STIHL Service Manual PDF

The STIHL Service Manual PDF provides comprehensive technical documentation for the maintenance, repair, and troubleshooting of STIHL power tools, including chainsaws, trimmers, blowers, and hedge trimmers. It contains detailed instructions, exploded diagrams, parts lists, torque specifications, diagnostic procedures, and safety warnings essential for professional technicians and qualified users. Below are key sections covering safety, tools, engine systems, fuel systems, electrical systems, troubleshooting, and parts ordering.

Safety Information & Warnings

Critical safety procedures to prevent injury during service operations.

Warning Symbol	Description
⚠️	Disconnect spark plug before any service to prevent accidental starting.
🔥	Allow engine to cool completely before servicing to avoid burns.
🧤	Wear cut-resistant gloves when handling sharp cutting attachments.
👁️	Always wear safety glasses to protect eyes from debris and fluids.
💨	Work in a well-ventilated area when handling fuel or cleaning chemicals.
📏	Use only STIHL-approved tools and replacement parts.
🧯	Keep a fire extinguisher nearby when testing or repairing fuel systems.
🔧	Follow torque specifications precisely to avoid component failure.

Required Tools & Equipment

Specialized tools needed for STIHL equipment service.

1. STIHL piston stop tool for engine timing and flywheel removal.
2. Carburetor adjustment tool (splined or flat type depending on model).
3. Chain breakage tool and rivet spinner for chainsaw chain service.
4. Compression tester and vacuum gauge for engine diagnostics.
5. Torque wrench (inch-pounds and foot-pounds ranges).
6. Feeler gauges for setting ignition points (older models) and valve clearances.
7. STIHL diagnostic software and interface cable (for electronic ignition models).

WARNING! Using incorrect tools can damage components and void warranty. Always refer to the specific manual for tool requirements.

Engine Specifications & Systems

Technical data for common STIHL engine series (e.g., MS 170, MS 250, FS 56, BR 600).

• Engine Type: 2-stroke air-cooled gasoline engine (most models).
• Displacement: Ranges from 30.1 cc to 91.1 cc for common models.
• Fuel/Oil Mix: 50:1 ratio with STIHL HP Ultra or equivalent ISO-L-EGD certified oil.
• Ignition System: Electronic CDI (Capacitor Discharge Ignition).
• Carburetor: Walbro or Zama diaphragm carburetor with adjustable H, L, and LA screws.
• Compression: Typically 120-150 PSI for a healthy engine.
• Starting System: Recoil starter with decompression valve (on some models).

Fuel System Service

Procedures for servicing the fuel tank, lines, filter, and carburetor.

1. Drain fuel tank completely into an approved container.
2. Replace in-tank fuel filter and inspect fuel lines for cracks or hardening.
3. Clean external carburetor surfaces before disassembly to prevent contamination.
4. Disassemble carburetor, clean all jets and passages with compressed air.
5. Replace diaphragm, gaskets, and needle valve as part of a rebuild kit.
6. Set initial carburetor adjustments: L screw 1 turn out, H screw 1 turn out (consult manual for exact specs).
7. Perform final adjustment with engine at operating temperature using a tachometer.

CAUTION! Never use wire or drill bits to clean jets; this alters calibration. Use only carburetor cleaner and air.

Ignition & Electrical System

Testing and replacement of ignition modules, spark plugs, and switches.

Spark Plug: Use specified type (e.g., BOSCH WSR6F, NGK BPMR7A). Gap: 0.020 inches (0.5 mm).

Ignition Module Test: Use a STIHL ignition tester or multimeter to check for spark output. Resistance values vary by model.

Switch Testing: Check for continuity in OFF/RUN positions. The switch must break the connection to the ignition module's kill wire.

Flywheel & Key: Inspect for sheared woodruff key if timing is incorrect. Torque flywheel nut to specification (e.g., 40 Nm).

Cutting Attachment Service

Maintenance for chainsaw bars, chains, trimmer heads, and blades.

1. Chainsaw Chain Sharpening: Use correct round file size (e.g., 5/32" for 3/8" pitch). Maintain 30° cutting angle and 10° top plate angle.
2. Bar Maintenance: Clean bar groove, flip bar regularly for even wear, and check for "rail dressing."
3. Trimmer Line: Wind .095" or .105" line onto spool in direction of arrow. Do not overfill.
4. Blade Sharpening: Sharpen hedge trimmer and brush cutter blades with a flat file, maintaining original bevel.

Tip: Always tension the chainsaw chain with the bar nose elevated. Chain should snap back when pulled from the bar.

Troubleshooting Guide

Diagnostic flowcharts for common STIHL equipment problems.

Symptom	Possible Cause	Corrective Action
Engine won't start	No spark, flooded, fuel issue	Check spark, dry plug, verify fuel flow and filter.
Engine starts then dies	Clogged fuel filter, carburetor, tank vent	Replace filter, clean carb, check tank vent hose.
Loss of power	Clogged air filter, spark arrestor, improper carb adjustment	Clean/replace filter, clean spark arrestor screen, adjust carb.
Chain/trim head won't turn	Clutch worn, drive shaft damaged, gearbox failure	Inspect clutch shoes, check for bent shaft, service gearbox.
Excessive vibration	Unbalanced cutting attachment, loose components, bent crankshaft	Balance attachment, tighten bolts, inspect crankshaft.
Oil not dispensing	Clogged oiler holes, faulty oil pump, wrong oil viscosity	Clean bar oil holes, test/replace pump, use STIHL bar oil.

Parts Diagrams & Ordering

How to use exploded-view diagrams and order genuine STIHL parts.

Each manual section includes a numbered parts diagram. Match the item number to the parts list to get the correct part number (e.g., 1140 640 2000). Order through authorized STIHL dealers or the online STIHL parts portal. Using non-genuine parts may affect performance and void warranty.

Maintenance Schedules

Recommended service intervals for daily, weekly, and seasonal maintenance.

• Daily: Clean air filter, check chain tension and sharpness, inspect for loose fasteners.
• Weekly (or 10 hours): Clean cooling fins, check spark plug condition, clean exterior.
• Seasonal (or 50 hours): Replace fuel filter, clean/replace spark arrestor, inspect clutch and drum.
• Annual (or 100 hours): Clean carburetor, check fuel lines, inspect piston through exhaust port, service gearbox (on trimmers).

CAUTION! Failure to follow maintenance schedules can lead to premature wear and unsafe operation.

Warranty & Support

STIHL limited warranty terms and how to access technical support.

STIHL offers a limited warranty for residential and commercial use; terms vary by region and product. Proof of purchase from an authorized dealer is required. For technical support, contact an authorized STIHL servicing dealer. Online resources include the STIHL USA website (www.stihlusa.com) for manuals and FAQs. Do not attempt repairs covered under warranty as this may void coverage.

Frequently Asked Questions

Question	Answer
Where can I download a STIHL service manual PDF?	Authorized manuals are available through STIHL dealers or the official STIHL website with a valid serial number.
What is the default carburetor setting?	Typically 1 turn out on both High (H) and Low (L) speed screws, but always confirm in the specific model's manual.
How do I reset the maintenance reminder on an M-Tronic saw?	Start the saw and let it idle for 3 minutes without touching the throttle. The reset is automatic.
Can I use regular motor oil for the bar and chain?	No. Use only STIHL bar oil or a dedicated chainsaw oil with the proper tackifiers for adhesion.
My trimmer head keeps jamming. Why?	Often caused by overfilling the spool, using incorrect line diameter, or a worn bump feed mechanism.

Note: This manual is a general guide. Always refer to the model-specific service manual for precise instructions.

Service Support: 1-800-467-8445; www.stihlusa.com