MS 170 Chainsaw Manual

The MS 170 is a lightweight, compact chainsaw designed for homeowners and occasional users. It features a 30.1cc engine, Easy2Start system, anti-vibration handles, STIHL Quickstop chain brake, Ematic lubrication system, and tool-free chain tensioning. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: 30.1cc engine, 16" guide bar, STIHL Oilomatic saw chain, anti-vibration system, side-access chain tensioner, transparent fuel tank.

Feature	Description
Engine	30.1cc single-cylinder, 2-stroke gasoline engine
Easy2Start	Reduces pulling force required for starting
STIHL Quickstop	Inertia-activated chain brake for safety
Ematic System	Efficient chain lubrication with reduced oil consumption
Anti-Vibration	Reduces vibration for user comfort
Chain Tensioning	Tool-free side access adjustment
Fuel Tank	Transparent for easy fuel level monitoring
Guide Bar	16" length (standard)
Weight	Approximately 8.6 lbs (without bar and chain)
Ignition	Electronic ignition with single-lever master control

Safety Information

Read all instructions before operation. Wear proper PPE.

1. Personal Protective Equipment: Always wear safety glasses, hearing protection, gloves, chainsaw chaps, and sturdy boots.
2. Work Area Safety: Clear area of bystanders, especially children. Ensure secure footing.
3. Chain Brake: Test chain brake before each use by pushing front hand guard forward.
4. Kickback Zone: Avoid contact with upper quadrant of guide bar tip.
5. Fuel Safety: Mix fuel outdoors, away from sparks. Use STIHL 2-stroke oil with 50:1 mix ratio.

WARNING! Chainsaws are dangerous. Failure to follow safety instructions can result in serious injury or death. Never operate when tired or under influence.

Assembly & Preparation

Assemble guide bar and chain. Fill with fuel and oil.

1. Attach Guide Bar & Chain: Place bar on studs, loop chain over sprocket and bar, adjust tension with side knob.
2. Fill Fuel: Use clean gasoline (89 octane min.) mixed with STIHL 2-stroke oil at 50:1 ratio.
3. Fill Chain Oil: Use STIHL chain oil or equivalent in separate oil tank.
4. Check Controls: Ensure throttle trigger, throttle lockout, and master control lever function properly.
5. Check Chain Brake: Push front hand guard forward; chain should stop immediately.

CAUTION! Ensure chain is properly tensioned - should snap back when pulled from bar. Loose chain can derail; overtightened chain can damage saw.

Specifications

• Engine Displacement: 30.1 cc
• Power Output: 1.5 kW (2.0 bhp)
• Fuel Tank Volume: 8.5 fl. oz. (0.25 L)
• Oil Tank Volume: 5.1 fl. oz. (0.15 L)
• Guide Bar Lengths: 16" (standard), 14" (optional)
• Chain Pitch: 3/8" PMM3
• Chain Gauge: 0.043" (1.1 mm)
• Weight (powerhead): 8.6 lbs (3.9 kg)
• Sound Pressure Level: 106 dB(A)
• Vibration Level: 4.5 m/s² (front), 5.5 m/s² (rear)

Controls and Components

Master Control Lever: Controls choke, start, run, and stop positions. Throttle Trigger Lockout: Must be depressed to engage throttle. Chain Brake/Hand Guard: Stops chain if activated. Decompression Valve: Reduces compression for easier starting (if equipped).

Main Components: 1. Rear handle with throttle trigger, 2. Front handle with hand guard, 3. Master control lever, 4. Fuel tank cap, 5. Oil tank cap, 6. Chain tensioner knob, 7. Muffler, 8. Spark plug, 9. Air filter cover, 10. Starter grip.

Starting & Stopping

Starting Procedure (Cold Engine):

1. Place saw on firm ground. Engage chain brake.
2. Press decompression valve (if equipped).
3. Set master control lever to choke position (full down).
4. Press throttle trigger lockout and squeeze throttle trigger once.
5. Pull starter rope until engine fires (usually 2-3 pulls).
6. Move master control lever to half-throttle position.
7. Pull starter rope until engine starts.
8. Blip throttle to disengage start position; chain brake can be released.

Stopping: Release throttle, let engine idle, push master control lever up to stop position.

Operating Instructions

Proper cutting techniques for safety and efficiency.

1. Firm Grip: Hold front handle with left hand, rear handle with right hand. Thumb under handle.
2. Body Position: Stand with feet shoulder-width apart, left foot slightly forward.
3. Starting Cut: Apply light pressure, let chain do the work. Don't force saw.
4. Kickback Prevention: Keep saw body close to your body; never cut with bar tip.
5. Bucking: Support log properly. Cut from top down. Watch for binding.
6. Limbing: Work from trunk outward. Be aware of spring-loaded branches.
7. Refueling: Stop engine completely and allow to cool before refueling.

WARNING! Never operate chainsaw above shoulder height or with one hand. Always be aware of where bar tip is pointing.

Maintenance Schedule

Interval	Task
Before each use	Check chain tension, sharpness, and lubrication; test chain brake
Daily	Clean air filter; check for loose fasteners
Weekly	Clean cooling fins; check spark plug condition
Monthly	Clean fuel filter; inspect anti-vibration elements
Every 3 months	Replace spark plug; clean carburetor air passage
Yearly	Have professional service check compression, bearings, etc.

Note: Maintenance intervals vary based on usage. Heavy use requires more frequent maintenance.

Chain & Bar Care

Proper chain maintenance ensures performance and safety.

1. Sharpening: Use round file (5/32" or 4.0mm) at 30° angle. File all cutters evenly.
2. Tensioning: Chain should be snug against bar but pull freely. Adjust when chain sags from bar.
3. Lubrication: Ensure oiler is working - look for oil spray when running at full throttle away from cutting area.
4. Bar Maintenance: Clean bar groove regularly. Flip bar monthly for even wear.
5. Depth Gauges: File down when sharpening chain (use depth gauge tool).

CAUTION! Always wear gloves when handling chain. A dull chain requires more force and increases kickback risk.

Storage

Proper storage prevents fuel system issues.

1. Short-term (under 30 days): Fill tank with fresh fuel mix, run briefly to circulate through system.
2. Long-term (over 30 days): Drain fuel tank completely. Run engine until it stops from fuel starvation.
3. Remove spark plug, add teaspoon of oil through spark plug hole, pull starter slowly to distribute.
4. Clean entire saw, especially cooling fins and air filter.
5. Store in dry place, bar and chain removed or loosened.

Important: Never store with fuel in tank for extended periods - fuel degrades and gums up carburetor.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Old fuel, flooded, spark plug	Use fresh fuel mix; wait if flooded; check/replace spark plug
Engine starts then dies	Clogged fuel filter, air filter	Replace fuel filter; clean air filter
Chain doesn't turn	Chain brake engaged, clutch, sprocket	Disengage chain brake; check clutch springs; inspect drive sprocket
Chain doesn't oil	Empty oil tank, clogged oiler	Fill oil tank; clean oil passages; check oil pump
Excessive vibration	Loose components, unbalanced chain	Tighten all fasteners; sharpen chain evenly
Poor cutting performance	Dull chain, incorrect filing	Sharpen chain properly; check depth gauges
Chain throws off bar	Loose chain, worn bar, damaged drive links	Properly tension chain; replace worn bar; inspect chain

Service: For repairs beyond basic maintenance, contact authorized STIHL servicing dealer.

Warranty: Limited warranty for residential use - see separate warranty documentation.