Stihl 009 Chainsaw Service Manual

The Stihl 009 is a lightweight, professional-grade gasoline chainsaw designed for a variety of cutting tasks. This service manual provides comprehensive information for maintenance, troubleshooting, and repair. It covers safety procedures, technical specifications, engine systems, fuel system, ignition system, cutting equipment, and step-by-step repair instructions. Always prioritize safety and use genuine Stihl parts for optimal performance and longevity.

1. Safety Information 2. Specifications & Identification 3. Maintenance Schedule 4. Engine Systems 5. Fuel System 6. Ignition System 7. Cutting Equipment 8. Carburetor Adjustment 9. Disassembly & Assembly 10. Troubleshooting 11. Torque Specifications

Safety Information

Operating and servicing a chainsaw involves significant risks. Always follow these fundamental safety rules.

Area	Precaution
Personal Protective Equipment (PPE)	Always wear chainsaw chaps, safety glasses, hearing protection, gloves, and steel-toe boots.
Workspace	Service in a clean, well-ventilated area. Keep away from sparks, open flames, and heat sources.
Fuel Handling	Use fresh fuel/oil mix (50:1). Do not smoke. Wipe up spills immediately.
Before Starting	Ensure chain brake is functional, chain is sharp and tensioned correctly, and all guards are in place.
During Operation	Maintain secure footing, hold saw with both hands, and be aware of kickback zone.
During Service	Disconnect spark plug wire before performing any work. Allow engine to cool completely.

Specifications & Identification

Key technical data and model identification points for the Stihl 009.

Engine Type: Single cylinder, two-stroke, air-cooled.
Displacement: 33.6 cc (2.05 cu. in.).
Power Output: 1.6 kW (2.1 hp).
Fuel/Oil Mix: 50:1 (Stihl HP Ultra or equivalent).
Ignition System: Electronic, breakerless.
Carburetor: Walbro or Zama diaphragm type.
Guide Bar Mount: Stihl 3005 series.
Recommended Bar Lengths: 12" to 16".
Idle Speed: 2,800 RPM.
Max Power Speed: 12,500 RPM.
Weight (powerhead): Approx. 4.2 kg (9.3 lbs).

Identification: Serial number and model designation are stamped on the crankcase.

Maintenance Schedule

Regular maintenance is critical for safe operation and long service life.

Before Each Use: Check chain tension and sharpness, inspect for loose fasteners, check throttle and chain brake operation.
Daily (or after each fuel tank): Clean air filter, check fuel filter in tank, clean cooling fins and guide bar groove.
Weekly (or every 10 operating hours): Clean spark arrestor screen (if equipped), inspect spark plug, clean exterior of saw.
Monthly (or every 20 operating hours): Check fuel line for cracks, inspect anti-vibration elements, check clutch and sprocket wear.
Annually (or every 100 operating hours): Replace fuel filter, inspect cylinder/piston through exhaust port, clean carburetor, check all gaskets and seals.

WARNING! Never perform maintenance on a hot saw or with the spark plug connected.

Engine Systems

Overview of the two-stroke engine components: cylinder, piston, crankshaft, bearings, and seals.

Cylinder & Piston Inspection: Remove muffler to inspect piston skirt and cylinder walls for scoring. Light scoring can be cleaned with fine emery cloth. Deep scoring requires replacement.

Crankcase Seals: Critical for engine vacuum/pressure. Test by pressurizing crankcase (not exceeding 7 psi) and checking for leaks with soapy water. Faulty seals cause lean run condition and engine failure.

Muffler: Clean carbon deposits regularly. A clogged muffler reduces power and increases operating temperature.

Fuel System

Components: Fuel tank, cap, lines, filter, and carburetor.

Fuel Lines: Inspect for brittleness or cracks. Replace if damaged.
Fuel Filter: Located in the fuel tank. Replace annually or when clogged.
Fuel Tank Vent: Ensure it is clear. A blocked vent creates a vacuum, stopping fuel flow.
Carburetor Diaphragms & Gaskets: Over time, these harden and fail, causing poor running. Service kit includes replacements.

Tip: Always use a clean, approved fuel container to prevent contamination.

Ignition System

Components: Flywheel, ignition module (coil), spark plug, and stop switch wire.

Spark Plug: Use Champion RCJ7Y or equivalent. Gap: 0.5 mm (0.020"). Check for fouling, correct heat range, and cracked porcelain.

Ignition Module Air Gap: Set to 0.3 mm (0.012") using a feeler gauge between the coil leg and flywheel magnet. Check for cracks or carbon tracking on the coil.

Testing: Use an ignition tester. A strong, blue spark across a 7mm gap indicates good coil. No spark? Check stop switch wire for continuity to ground (should be open circuit when switch is "on").

Cutting Equipment

Guide bar, saw chain, drive sprocket, and clutch.

Chain Tension: Correct when snug against bar but can be pulled around by hand. Tighten adjuster screw with bar tip raised. Chain should not sag from bar rails.
Bar Maintenance: Clean bar groove and oil holes daily. Flip bar regularly for even wear. Dress bar rails with a flat file if burred.
Sprocket: Inspect for wear (hook-shaped teeth). Replace sprocket and chain together if worn.
Clutch: Springs can break or lose tension. Drum should spin freely when engine is off. Replace if scored or worn.
Chain Sharpening: Maintain correct filing angle (typically 30°) and depth gauge clearance. Use correct round file size for chain pitch.

WARNING! A loose or dull chain is a major safety hazard and increases risk of kickback.

Carburetor Adjustment

Standard settings for initial adjustment. Final adjustment must be made with a warmed-up engine and a tachometer.

Screw	Function	Initial Setting
L (Low Speed)	Idle and low-speed fuel mixture	1 turn open from lightly seated
H (High Speed)	High-speed fuel mixture and max RPM	1 turn open from lightly seated
LA (Idle Speed)	Sets idle RPM	Adjust until chain just stops moving, then add 1/4 turn

Procedure: Start with initial settings. Warm up engine for 5 minutes. With chain stopped, adjust "L" screw for fastest, smoothest idle. Adjust "LA" screw to set correct idle speed (chain must not move). Adjust "H" screw to achieve max power speed of 12,500 RPM (requires tachometer). Re-check idle. Engine should accelerate smoothly without hesitation.

Disassembly & Assembly

Major steps for engine disassembly. Always refer to detailed diagrams.

Remove top cover, air filter, and carburetor.
Remove starter assembly, clutch, and drive sprocket.
Remove cylinder cover and muffler.
Remove cylinder base nuts. Carefully lift cylinder from crankcase.
Remove piston pin circlips. Heat piston if necessary and push out piston pin. Remove piston.
To split crankcase, remove all connecting screws. Separate case halves using a splitting tool. Do not pry.
Assembly: Reverse procedure. Use new gaskets and seals. Apply sealant to crankcase mating surfaces as specified. Torque all fasteners to specification.

CAUTION! Label all parts and take photos during disassembly. Organize fasteners.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine will not start	No spark, no fuel, flooded	Check spark, fuel in tank, line, and filter. Choke procedure. Pull with throttle locked open if flooded.
Engine starts but dies	Clogged fuel filter, tank vent, carburetor, faulty crank seal	Replace fuel filter. Check vent. Service carburetor. Perform crankcase pressure test.
Lacks power/overheats	Clogged air filter, muffler, incorrect carb adjustment, scored piston	Clean air filter and muffler. Adjust carburetor. Inspect piston through exhaust port.
Chain does not turn	Clutch worn, sprocket jammed, drive link damage	Inspect clutch springs and drum. Clean/replace sprocket. Check chain for damaged drive links.
Excessive vibration	Loose fasteners, unbalanced chain, damaged anti-vibration mounts	Tighten all fasteners. Sharpen chain evenly. Inspect and replace anti-vibration elements.
Oil not feeding to bar	Empty oil tank, clogged oil passages, faulty oil pump	Fill tank. Clean bar groove and oil holes. Check oil line and pump drive mechanism.

Torque Specifications

Critical fastener torque values (use calibrated torque wrench).

Cylinder Nuts: 20 Nm (15 ft-lb)
Spark Plug: 25 Nm (18 ft-lb)
Clutch: 40 Nm (30 ft-lb) - LEFT-HAND THREAD
Flywheel Nut: 40 Nm (30 ft-lb)
Crankcase Screws: 10 Nm (7.5 ft-lb)
Guide Bar Nuts: 12 Nm (9 ft-lb)
Muffler Screws: 8 Nm (6 ft-lb)

Service: For technical support and genuine parts, contact your authorized Stihl dealer or visit www.stihlusa.com.