stihl 031 chainsaw manual

The STIHL 031 is a professional-grade gasoline-powered chainsaw designed for demanding cutting tasks. This manual covers essential safety information, technical specifications, assembly instructions, operation procedures, maintenance schedules, and troubleshooting for the STIHL 031 chainsaw. Always read and understand this manual completely before operating the saw to ensure safe and efficient use.

Safety Information & Warnings

Operating a chainsaw is inherently dangerous. Failure to follow safety instructions can result in serious injury or death.

WARNING! Never operate the chainsaw when fatigued, under the influence of medication, alcohol, or drugs. Always wear appropriate Personal Protective Equipment (PPE).

Specifications & Features

• Engine Type: STIHL single-cylinder, two-stroke gasoline engine.
• Displacement: 49.0 cm³ (Approx. 3.0 cu. in.).
• Power Output: High torque design for demanding cuts.
• Fuel/Oil Mix: 50:1 ratio using STIHL HP Ultra or equivalent high-quality 2-stroke oil.
• Guide Bar Lengths: Compatible with 16" to 20" bars (as specified).
• Chain Pitch/Gauge: .325" pitch, .063" gauge (standard).
• Ignition System: Electronic ignition (CDI).
• Carburetor: Diaphragm-type with manual choke.
• Anti-Vibration System: Integrated to reduce operator fatigue.
• Chain Brake: Inertia-activated for kickback protection.

Assembly & Initial Setup

Assemble your chainsaw on a clean, stable surface.

1. Attach Guide Bar & Chain: Loosen bar nuts. Place chain over sprocket, ensuring cutting teeth face forward on top of bar. Fit bar onto studs. Adjust tension via side knob. Tighten bar nuts finger-tight, then final-tighten with tool after tension is set.
2. Fill Chain Oil Tank: Use STIHL chain oil or equivalent. Fill to marked level.
3. Mix Fuel: Use clean, unleaded gasoline (min. 89 octane) mixed with 2-stroke oil at 50:1. Shake container thoroughly.
4. Fill Fuel Tank: Clean area around cap. Pour mixed fuel carefully to avoid spillage.

CAUTION! Ensure chain is properly tensioned (sags slightly from bottom of bar) and moves freely by hand before starting.

Controls & Components

Familiarize yourself with all controls before starting the engine.

Main Components: Front Handguard/Chain Brake, Throttle Trigger, Throttle Trigger Lockout, Stop Switch (I/O), Choke Lever, Decompression Valve (if equipped), Master Control Lever (combines choke/run/stop functions on some models), Fuel Tank Cap, Chain Oil Tank Cap, Muffler, Spark Plug, Rear Handle, Front Handle.

Operation: The throttle trigger lockout must be depressed before the throttle trigger can be squeezed. The chain brake is engaged by pushing the front handguard forward. Disengage by pulling it back towards the operator.

Fuel & Lubrication

Using the correct fluids is critical for performance and engine life.

1. Fuel Mix: Always use 50:1 gasoline to 2-stroke oil mix. Do not use automotive oil or old gasoline.
2. Chain Oil: Use proper bar and chain oil for all temperatures. In cold weather, use winter-grade oil.
3. Check Oil Flow: Run saw at high idle over a light surface (cardboard). A line of oil should appear.
4. Gearbox Grease: Some models require periodic greasing of the clutch drum bearing (see Maintenance).

Tip: Empty the fuel tank if storing the saw for more than 30 days to prevent carburetor issues.

Starting & Stopping Procedures

Follow these steps precisely for safe starting.

Cold Start:

1. Place saw on firm ground. Engage chain brake.
2. Set Master Control Lever to Choke position (or pull choke lever out).
3. Press decompression valve (if equipped).
4. Pump primer bulb (if equipped) until fuel is visible.
5. Hold front handle with left hand, place right foot in rear handle. Pull starter cord sharply until engine 'pops'.
6. Move Master Control Lever to Half-Throttle/Run position (or push choke lever in).
7. Pull starter cord again until engine starts. Briefly blip throttle to disengage fast-idle.

Warm Start: Set lever to Run position. Do not use choke.

Stopping: Release throttle. Push stop switch to "O" or "STOP".

Operating Instructions

Proper technique ensures safety and cutting efficiency.

1. Stance: Stand with feet shoulder-width apart, left foot slightly forward for balance.
2. Grip: Hold front handle with left hand, rear handle with right hand. Thumbs must wrap underneath handles.
3. Cutting: Let the chain do the work. Apply light downward pressure. Use the bumper spike (dogs) to pivot into the wood.
4. Buckling: Support log fully. Make top cut first, then finish from underside to avoid pinching.
5. Limbing: Stand on left side of trunk. Cut branches from bottom to top, using trunk as a barrier.

WARNING! Never cut above shoulder height. Never operate the saw with one hand. Be aware of the reactive forces of Push, Pull, and Kickback.

Chain Maintenance & Sharpening

A sharp chain is a safe and efficient chain.

1. Check Sharpness: Chain produces fine sawdust, not coarse chips. It pulls itself into the wood.
2. File Size: Use a round file matching the chain's pitch (e.g., 4.0mm / 5/32" for .325" pitch).
3. Filing Angle: Maintain factory angle (typically 30°). Use a filing guide.
4. Procedure: Secure bar. Mark starting cutter. File from inside out, applying equal strokes to each cutter. File all cutters to the same length.
5. Depth Gauges: Use a depth gauge tool to lower rakers (depth gauges) after several sharpenings.

CAUTION! Always wear heavy gloves when handling the chain. A dull chain increases the risk of kickback.

Regular Maintenance Schedule

Storage Instructions

Proper storage prevents fuel system damage and corrosion.

1. Short-Term (under 30 days): Run carburetor dry or add fuel stabilizer. Store in a dry, locked place.
2. Long-Term: Drain ALL fuel from tank and carburetor. Run engine until it stops. Remove chain, clean and soak in oil. Clean entire saw. Store in a dry, frost-free location.

CAUTION! Gasoline left in the carburetor will form varnish and clog passages, requiring professional service.

Troubleshooting Guide

Service: For repairs beyond basic maintenance, contact an authorized STIHL servicing dealer. Use only genuine STIHL parts.