Manual for Stihl 031

The Stihl 031 is a professional-grade gasoline-powered chainsaw designed for demanding cutting tasks. It features a robust engine, anti-vibration system, automatic chain oiling, and safety mechanisms like a chain brake and throttle lockout. Below are key sections covering safety, features, assembly, operation, maintenance, troubleshooting, and specifications.

Features at a Glance

Key components: Engine, Fuel Tank, Oil Tank, Chain Brake Lever, Throttle Trigger, Throttle Lockout, Decompression Valve, Anti-Vibration System.

Feature	Description
Engine Type	2-stroke, single-cylinder gasoline engine
Displacement	Approx. 51 cc
Fuel System	Diaphragm carburetor
Ignition System	Electronic ignition (CDI)
Chain Brake	Inertia-activated safety brake
Anti-Vibration System	Reduces operator fatigue
Automatic Oiling	Lubricates chain and bar during operation
Decompression Valve	Easier starting
Bar Length Options	Typically 16" to 20"
Weight (without bar/chain)	Approx. 5.7 kg (12.6 lbs)

Assembly & Preparation

Unpack and inspect all parts. Assemble on a clean, stable surface.

1. Attach Guide Bar and Chain: Place bar on mounting studs, fit chain in correct cutting direction, tension chain appropriately.
2. Fill Fuel Tank: Use fresh gasoline mixed with high-quality 2-stroke oil at the specified ratio (e.g., 50:1).
3. Fill Chain Oil Tank: Use proper bar and chain oil.
4. Check Controls: Ensure throttle trigger, lockout, and chain brake function smoothly.

WARNING! Always wear appropriate Personal Protective Equipment (PPE) including gloves, eye protection, hearing protection, and chainsaw chaps.

First-Time Operation

Before starting, ensure you are in a well-ventilated, open area.

1. Starting Procedure: Set master control lever to cold start position (choke on). Activate decompression valve if equipped. Pull starter rope sharply until engine fires. Move lever to warm start position and pull again to start.
2. Warm-up: Allow engine to idle for a brief period.
3. Chain Brake Test: With engine off, engage and disengage the chain brake to ensure it functions.
4. Test Throttle: Squeeze throttle trigger to ensure chain begins to move and returns to idle.

CAUTION! Never start the saw unless the chain brake is disengaged and you have a firm footing.

Specifications

• Model: Stihl 031 AV (Anti-Vibration)
• Engine Power: Approx. 3.0 kW (4.0 hp)
• Fuel Capacity: Approx. 0.55 liters (18.6 fl oz)
• Oil Tank Capacity: Approx. 0.26 liters (8.8 fl oz)
• Recommended Fuel Mix: Unleaded gasoline with Stihl 2-stroke oil, 50:1 ratio
• Idle Speed: 2,800 rpm
• Max Engine Speed: 13,500 rpm
• Sound Pressure Level: Approx. 105 dB(A)
• Vibration Level (front/rear handle): Approx. 5.5/4.5 m/s²

Controls and Functions

Master Control Lever: Combines stop switch, choke, and run positions. Throttle Trigger: Controls engine speed. Throttle Lockout: Must be depressed to allow throttle operation. Chain Brake Lever: Manually engages brake; also inertia-activated. Decompression Valve: Reduces cylinder pressure for easier starting.

Operation: To start, set lever to cold start (choke). Pull starter. After engine fires, move lever to run. Use throttle lockout and trigger to control cutting speed.

Chain & Bar Setup

Proper chain tension is critical for safety and performance.

1. Loosen bar nuts with combination wrench.
2. Lift tip of bar and adjust tensioning screw until chain fits snugly against bar but can be pulled around by hand.
3. Retighten bar nuts while holding tip up.
4. Check tension again after tightening; it should not sag from the bar.

Tip: Always check chain tension when the chain is cold. A hot chain expands and will be tighter.

Cutting Techniques

Supports felling, limbing, bucking, and pruning.

1. Felling: Plan escape path. Make notch cut and back cut. Use wedges if necessary.
2. Limbing: Stand on opposite side of log from limbs. Cut from top down, using bar as a shield.
3. Bucking: Support log fully. Cut from top, avoid pinching bar.
4. Pruning: Use bottom of bar for cutting. Beware of spring-back.

WARNING! Never cut above shoulder height. Be aware of kickback zone (upper quadrant of bar tip). Always hold saw firmly with both hands.

Safety Features

Chain Brake: Stops chain within milliseconds if activated manually or by inertia. Throttle Lockout: Prevents accidental throttle engagement. Right-Hand Guard: Protects hand from a broken or derailed chain. Anti-Vibration System: Reduces fatigue and improves control.

Care & Storage

Clean saw after each use. Check air filter, spark plug, and chain sharpness regularly.

Storage: For long-term storage, drain fuel tank and run carburetor dry. Remove chain and bar, clean and oil them. Store in a dry place.

CAUTION! Fuel is flammable. Store fuel mix in an approved container away from heat sources.

Regulatory Information

Complies with applicable ANSI and EPA standards for outdoor power equipment. Contains parts that may be subject to California Proposition 65 warnings. Stihl is a registered trademark of Andreas Stihl AG & Co. KG. For genuine parts and service, contact an authorized Stihl dealer.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine will not start	Old fuel, flooded engine, spark plug	Use fresh fuel mix. Wait if flooded. Check/replace spark plug.
Engine starts but dies	Clogged air filter, carburetor adjustment	Clean or replace air filter. Have carburetor adjusted by dealer.
Chain does not turn	Chain brake engaged, clutch, sprocket	Disengage chain brake. Check clutch and drive sprocket for wear.
Excessive vibration	Loose parts, unbalanced chain	Tighten all fasteners. Sharpen and tension chain properly.
Chain throws oil but doesn't cut well	Dull chain	Sharpen chain with correct file size and angle.

Service: For major repairs, contact an authorized Stihl servicing dealer.