Stihl MS 270 Manual

The Stihl MS 270 is a professional-grade chainsaw featuring a powerful 50.2cc engine, advanced anti-vibration system, QuickStop® inertia chain brake, STIHL Ematic™ lubrication system, and easy-start technology. Designed for demanding cutting tasks, it offers reliable performance, enhanced safety features, and ergonomic handling. Below are key sections covering safety, features, operation, maintenance, troubleshooting, and specifications.

Features at a Glance

Key components: 50.2cc engine, anti-vibration system, QuickStop® chain brake, STIHL Ematic™ lubrication, side-access chain tensioner, and decompression valve.

Feature	Description
Engine Displacement	50.2 cc, 2-stroke engine
Power Output	3.0 bhp for robust cutting performance
Guide Bar Lengths	16" to 20" (standard 18")
Anti-Vibration System	Reduces operator fatigue during extended use
QuickStop® Inertia Chain Brake	Automatically stops chain in kickback situations
STIHL Ematic™ System	Efficient chain lubrication with reduced oil consumption
Decompression Valve	Easier starting with reduced pulling effort
Side-Access Chain Tensioner	Allows easy chain adjustment without removing cover
Fuel Tank Capacity	500 ml (16.9 fl. oz.)
Oil Tank Capacity	260 ml (8.8 fl. oz.)

Safety Instructions

Read and understand all safety warnings before operation.

1. Personal Protective Equipment (PPE): Always wear safety glasses, hearing protection, gloves, chainsaw chaps, and sturdy boots.
2. Clear Work Area: Ensure no bystanders, pets, or obstacles within 15 feet.
3. Inspect Chainsaw: Check for loose parts, damaged chain, and proper lubrication before each use.
4. Proper Grip: Hold with both hands, right hand on rear handle, left on front.
5. Kickback Awareness: Avoid contact with bar nose; use reduced-kickback chain.

WARNING! Failure to follow safety instructions can result in serious injury or death. Never operate a chainsaw while tired, under the influence, or in poor weather conditions.

Assembly & Preparation

Unpack and assemble components carefully.

1. Attach Guide Bar & Chain: Place bar on studs, loop chain around sprocket and bar with cutters facing forward, adjust tension via side-access knob.
2. Fill Fuel: Use STIHL MotoMix® or 50:1 gasoline/oil mixture. Fill fuel tank to marked level.
3. Fill Chain Oil: Use STIHL HP Ultra or equivalent bar & chain oil. Fill oil tank.
4. Check Controls: Ensure throttle trigger, throttle lockout, and chain brake function properly.

CAUTION! Use only recommended fuels and oils. Improper mixtures can cause engine damage.

Specifications

• Engine: 50.2 cc single-cylinder 2-stroke.
• Power: 3.0 bhp at 9,000 rpm.
• Fuel Consumption: Approx. 580 g/kWh.
• Sound Pressure Level: 106 dB(A).
• Vibration Levels: Front handle 4.2 m/s², rear handle 3.8 m/s².
• Weight (without cutting equipment): 5.4 kg (11.9 lbs).
• Ignition System: STIHL Electronic Ignition (CDI).
• Carburetor: STIHL diaphragm carburetor with fuel pump.
• Recommended Guide Bar Lengths: 16", 18", 20".
• Chain Pitch/Gauge: 3/8" PM, .050".

Controls and Functions

Master Control Lever: Combines stop switch, choke, and start positions. Throttle Trigger: Controls engine speed. Throttle Lockout: Must be depressed to engage throttle. Chain Brake Lever: Manual activation; also inertia-activated. Decompression Valve: Reduces cylinder pressure for easier starting. Side-Access Chain Tensioner: Adjusts chain tension without tools.

Maintenance Points: Air filter cover, spark plug, fuel and oil caps, chain catcher, muffler.

Starting & Stopping

Cold Start:

1. Engage chain brake by pushing lever forward.
2. Set Master Control to choke position (full down).
3. Press decompression valve (if equipped).
4. Place on ground, hold front handle with left foot, pull starter cord briskly until engine fires.
5. Move Master Control to half-throttle position, pull until engine starts.
6. Blip throttle to disengage fast-idle, release chain brake.

Warm Start: Master Control in run position; no choke needed.

Stopping: Release throttle, move Master Control to STOP position.

Operation & Cutting Techniques

Basic Cutting: Let chain do the work; avoid forcing. Use full throttle during cuts.

1. Felling: Plan escape path. Make notch cut 1/3 of tree diameter, then back cut leaving hinge.
2. Limbing: Work from trunk outward. Support log off ground.
3. Bucking: Cut from top side when possible. Use wedges for pinched cuts.
4. Kickback Prevention: Maintain firm grip, do not cut with bar nose, keep chain sharp.

Tip: Regularly check chain tension; a loose chain can derail or break.

Maintenance & Cleaning

Daily/Pre-Use: Check chain tension, sharpness, lubrication. Clean air filter. Inspect for damage.

Weekly: Clean cooling fins, check spark plug, clean fuel filter.

Monthly: Clean carburetor air passage, check all nuts/bolts for tightness.

CAUTION! Always disconnect spark plug wire before performing maintenance. Use only STIHL-approved parts.

Chain & Bar Care

Sharpening: Use round file matching chain pitch (typically 5.5mm). Maintain 30° cutting angle, 10° top plate angle. File all cutters evenly.

Bar Maintenance: Clean bar groove weekly, flip bar monthly for even wear. Dress bar rails with flat file if burred.

Lubrication: Ensure oiler is working; adjust flow via screw if needed. Always use clean, high-quality bar & chain oil.

Storage

Long-Term Storage (over 30 days):

1. Drain fuel tank and run engine until carburetor is dry.
2. Remove chain, clean and soak in oil. Store bar clean and oiled.
3. Clean entire saw, especially cooling fins and air filter.
4. Store in dry, cool place, covered to prevent dust.

WARNING! Never store with fuel in tank; fuel can degrade and damage carburetor.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No spark, flooded, stale fuel	Check spark plug; use fresh fuel mix; follow cold start procedure.
Engine runs poorly	Clogged air filter, carburetor issues	Clean/replace air filter; have carburetor serviced.
Chain doesn't turn	Brake engaged, clutch worn, chain too tight	Disengage brake; check clutch; adjust chain tension.
Excessive vibration	Loose components, unbalanced chain	Tighten all fasteners; sharpen chain evenly.
Chain throws oil	Over-oiling, wrong oil viscosity	Adjust oiler; use recommended bar & chain oil.
Chain dulls quickly	Cutting dirty wood, improper filing	Avoid ground contact; sharpen at correct angles.

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

Support: STIHL USA, 1-800-467-8445, www.stihlusa.com