Stihl MS171 Manual

The Stihl MS171 is a lightweight, easy-to-handle chainsaw designed for homeowners and occasional users. It features a low-emission engine, easy-start system, anti-vibration handles, chain brake for safety, tool-less fuel and oil caps, and a side-access chain tensioner. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Engine, guide bar, saw chain, chain brake, anti-vibration system, fuel and oil caps, side-access chain tensioner.

Feature	Description
Engine	Low-emission 2-stroke engine with easy-start system
Guide Bar	Available in various lengths (e.g., 16")
Saw Chain	Oregon or Stihl Picco Micro 3 chain
Chain Brake	Inertia-activated safety feature to stop chain
Anti-Vibration System	Reduces user fatigue during operation
Fuel and Oil Caps	Tool-less design for easy refueling
Side-Access Chain Tensioner	Allows chain adjustment without tools
Throttle Trigger	Controls engine speed; includes throttle lockout
Master Control Lever	Combines choke, start, and run positions
Decompression Valve	Reduces pulling force for easier starting

Safety Information

Read all instructions before use. Wear protective gear.

1. Personal Protective Equipment: Wear safety glasses, hearing protection, gloves, chainsaw chaps, and sturdy boots.
2. Work Area Safety: Clear area of obstacles; ensure secure footing; keep bystanders away.
3. Chain Brake: Test before each use; engage when carrying or not cutting.
4. Fuel Safety: Refuel in well-ventilated area; avoid sparks; use approved fuel mix.

WARNING! Risk of kickback! Hold saw firmly with both hands; do not cut with tip of bar.

Assembly & Preparation

Assemble saw before first use.

1. Attach guide bar and chain: Place bar on studs; fit chain with cutters facing forward; tension properly.
2. Fill fuel tank: Use fresh fuel mix (50:1 gasoline to 2-stroke oil).
3. Fill chain oil tank: Use Stihl chain oil or equivalent.
4. Check chain lubrication: Run saw briefly and check for oil on bar tip.

CAUTION! Ensure chain is properly tensioned—snug but movable by hand.

Specifications

• Engine Displacement: 30.1 cc.
• Power Output: 1.5 kW / 2.0 hp.
• Fuel Capacity: 0.25 L (8.5 fl. oz).
• Chain Oil Capacity: 0.15 L (5.1 fl. oz).
• Weight (without bar/chain): 3.9 kg (8.6 lbs).
• Guide Bar Lengths: Typically 12" to 16".
• Chain Pitch/Gauge: 3/8" PMM3, 0.043" (1.1 mm).
• Sound Power Level: 106 dB(A).
• Vibration Levels: Front handle 3.5 m/s²; rear handle 4.5 m/s².

Controls and Components

Familiarize yourself with controls before operation.

Front Handle: Includes throttle trigger, throttle lockout, and hand guard.

Rear Handle: Contains master control lever (choke/start/run), decompression valve, and stop switch.

Right Side: Chain brake lever, side-access chain tensioner, fuel and oil caps.

Left Side: Muffler, spark plug, and chain catcher.

Starting & Stopping

Starting procedure for cold and warm engines.

1. Place saw on firm ground; engage chain brake.
2. Press decompression valve (if equipped).
3. Set master control lever to choke position (cold start) or half-throttle (warm).
4. Hold front handle with left hand, place right foot in rear handle.
5. Pull starter rope briskly until engine fires.
6. Move lever to run position; pull again to start.
7. To stop: Release throttle; press stop switch.

Tip: Do not drop-start or start above waist height.

Operation Guidelines

Proper cutting techniques for safety and efficiency.

1. Hold saw firmly: Left hand on front handle, right on rear.
2. Stand to side: Keep body offset from cutting plane.
3. Let chain do the work: Apply light pressure; avoid forcing.
4. Bucking: Support log; cut from top; watch for binding.
5. Limbing: Cut from trunk outward; beware of springback.
6. Kickback prevention: Maintain firm grip; do not cut with upper tip.

WARNING! Never operate with one hand or above shoulder height.

Maintenance Schedule

Regular maintenance ensures longevity and safety.

Interval	Task
Before each use	Check chain tension, lubrication, and chain brake function
After each use	Clean air filter; inspect guide bar and chain
Every 10 hours	Clean spark arrestor screen; check fuel filter
Every 20 hours	Replace air filter; inspect spark plug
Every 50 hours	Replace spark plug; clean cooling fins
Annually	Professional servicing recommended

Chain & Bar Care

Proper care extends chain and bar life.

1. Sharpening: Use round file and guide; maintain correct angle (30°).
2. Depth gauges: File to proper height (0.65 mm) with flat file.
3. Bar maintenance: Clean groove; flip bar regularly; dress rails.
4. Lubrication: Always use chain oil; check oil flow frequently.

CAUTION! Wear gloves when handling chain; it is sharp.

Storage Instructions

Prepare saw for storage to prevent damage.

1. Empty fuel tank or add fuel stabilizer.
2. Run engine until carburetor is dry.
3. Remove chain; clean and oil it.
4. Clean entire saw; store in dry, secure place.

CAUTION! Do not store with fuel in tank for more than 30 days without stabilizer.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No fuel, flooded, spark plug	Check fuel; wait if flooded; clean/replace spark plug.
Engine runs poorly	Dirty air filter, fuel mix	Clean air filter; use fresh 50:1 fuel mix.
Chain doesn't turn	Chain brake engaged, clutch	Disengage chain brake; check clutch drum and spring.
Chain throws oil	Overfilled oil tank	Drain excess oil; check oiler setting.
Excessive vibration	Loose parts, damaged chain	Tighten all fasteners; inspect chain for damage.
Chain dulls quickly	Cutting dirty wood, improper sharpening	Avoid ground contact; sharpen correctly.

Service: For repairs, contact authorized Stihl dealer.

Support: Visit www.stihlusa.com or call 1-800-467-8445.