MS250 Chainsaw Owner's Manual

The MS250 is a professional-grade gasoline-powered chainsaw designed for demanding cutting tasks. It features a powerful 2-stroke engine, automatic chain oiling, anti-vibration system, Quickstop® inertia-activated chain brake, STIHL Ematic™ lubrication system, and side-access chain tensioner. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Assembly & Preparation 3. First-Time Operation 4. Specifications 5. Controls and Functions 6. Fuel & Lubrication 7. Chain & Bar Maintenance 9. Safety Features 10. Care & Storage 11. Regulatory Information 12. Troubleshooting

Features at a Glance

Key components: 2-stroke engine, guide bar, cutting chain, chain brake handle, throttle trigger, master control lever, fuel tank, oil tank.

Feature	Description
Engine Type	2-stroke single cylinder gasoline engine
Displacement	45.4 cc (2.77 cu. in.)
Power Output	2.6 kW (3.5 bhp)
Fuel Tank Capacity	0.47 L (16 oz)
Oil Tank Capacity	0.26 L (8.8 oz)
Guide Bar Length	16" (40 cm) standard
Chain Pitch	3/8" PMM3
Weight (without cutting attachment)	4.9 kg (10.8 lbs)
Ignition System	Electronic ignition (CDI)
Anti-Vibration System	STIHL anti-vibration with buffer elements

Assembly & Preparation

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

Attach guide bar and chain: Place bar on studs, fit chain with drive links in bar groove, tension properly.
Fill fuel tank: Mix high-quality 2-stroke oil with unleaded gasoline (50:1 ratio).
Fill chain oil tank: Use STIHL chain oil or equivalent.
Check chain brake: Ensure brake functions correctly by pulling handle forward.

WARNING! Always wear protective equipment: helmet, eye protection, hearing protection, gloves, chainsaw chaps, and steel-toe boots.

First-Time Operation

Starting procedure for cold and warm engine.

Set master control lever to cold start position (choke).
Press decompression valve (if equipped).
Place saw on ground, hold front handle with left hand, place right foot in rear handle.
Pull starter rope briskly until engine fires.
Move master control to half-throttle position, pull until engine starts.
Briefly blip throttle to disengage fast idle.

CAUTION! Never drop-start the chainsaw. Always maintain secure footing and grip.

Specifications

Engine: STIHL 2-MIX engine technology.
Powerhead Weight: 4.9 kg (10.8 lbs).
Sound Pressure Level: 106 dB(A).
Vibration Levels: Left/Right 4.2 m/s², Front/Rear 2.8 m/s².
Fuel Consumption: Approx. 580 g/kWh.
Lubrication System: Automatic with adjustable flow.
Chain Brake: Quickstop® inertia-activated.
Chain Tensioning: Side-access without tools.
Warranty: Limited warranty for personal use.

Controls and Functions

Master Control Lever: Combines choke, throttle lock, and stop functions. Throttle Trigger: Controls engine speed. Chain Brake Handle: Front hand guard activates brake when pushed forward. Decompression Valve: Reduces pulling force for starting. Throttle Lockout: Must be depressed to operate throttle.

Adjustments: Chain tension (side knob), oil flow (screwdriver slot), carburetor (by authorized dealer only).

Fuel & Lubrication

Fuel: Mix STIHL 2-stroke oil with unleaded gasoline (min. 89 octane) at 50:1 ratio. Chain Oil: Use STIHL chain oil or approved alternative.

Always mix fuel in approved container, not in saw tank.
Clean area around fuel cap before opening.
Check oil flow by running saw briefly over light surface.
Adjust oil flow for cutting conditions (more for hard/dry wood).

Tip: Use fresh fuel mix; do not store mixed fuel longer than 30 days.

Chain & Bar Maintenance

Regular maintenance ensures optimal performance and safety.

Chain sharpening: Use round file and guide; maintain 30° cutting angle.
Depth gauge adjustment: File rakers to 0.65 mm (0.025") below cutters.
Bar maintenance: Clean groove weekly; flip bar monthly for even wear.
Chain tension: Check frequently when new; chain should snap back when pulled from bar.
Sprocket inspection: Replace if worn (teeth hook-shaped).

WARNING! Always stop engine and wear gloves when handling chain. Never use damaged or worn cutting attachments.

Safety Features

Quickstop® Chain Brake: Stops chain within milliseconds if activated. Throttle Lockout: Prevents accidental throttle operation. Right-Hand Guard: Protects from kickback. Chain Catcher: Prevents broken chain from striking operator. Decompression Valve: Eases starting. Anti-Vibration System: Reduces operator fatigue.

Care & Storage

Clean saw after each use. For storage longer than 30 days:

Drain fuel tank and run engine until it stops.
Remove spark plug, add teaspoon of oil, pull starter slowly to coat cylinder.
Clean entire saw, especially cooling fins and air filter.
Store in dry place, cover to prevent dust accumulation.

CAUTION! Never pressure wash; water can enter engine and controls.

Regulatory Information

EPA Phase II compliant. Meets ANSI B175.1 safety standards. CARB certified for sale in California. Contains parts manufactured in Germany, USA, and Brazil. For genuine STIHL parts and service, contact authorized STIHL dealers only. © STIHL Incorporated. STIHL and the STIHL logo are registered trademarks.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Old fuel, clogged filter, spark plug	Use fresh fuel mix; clean/replace air filter; check spark plug gap (0.5 mm).
Engine runs poorly	Dirty carburetor, fuel line	Clean fuel filter; check fuel line for cracks; have dealer service carburetor.
Chain doesn't oil	Empty tank, clogged ports	Fill oil tank; clean oil ports in bar; check oil pump function.
Chain comes off bar	Loose chain, worn bar	Tension chain properly; replace if bar groove is worn over 0.8 mm.
Excessive vibration	Loose parts, unbalanced chain	Tighten all fasteners; sharpen chain evenly; check anti-vibration mounts.

Service Intervals: Air filter - clean daily; Spark plug - replace annually; Fuel filter - replace every 3 months.

Dealer Locator: 1-800-GO-STIHL; www.stihlusa.com