Stihl Chainsaw MS250 Manual

The STIHL MS 250 is a professional-grade gasoline-powered chainsaw designed for demanding cutting tasks. It features a powerful engine with STIHL anti-vibration system, QuickStop® inertia-activated chain brake, side-access chain tensioner, easy-start system, and STIHL Ematic™ lubrication system. Below are key sections for safety, features, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Engine with electronic ignition, anti-vibration system, QuickStop® chain brake, side-access chain tensioner, combined choke/stop control, STIHL Ematic™ lubrication system.

Feature	Description
Engine Displacement	45.4 cc (2.77 cu. in.)
Power Output	2.6 kW (3.5 bhp)
Guide Bar Lengths	16" or 18" (optional)
Fuel Tank Capacity	0.53 US pt (0.25 l)
Oil Tank Capacity	0.26 US pt (0.125 l)
Weight (powerhead)	10.8 lbs (4.9 kg)
Anti-Vibration System	STIHL standard design
Chain Brake	QuickStop® inertia-activated
Starting System	STIHL Easy2Start™
Chain Lubrication	STIHL Ematic™ system

Safety Information

Read and understand all safety warnings before operation.

1. Personal Protective Equipment: Always wear safety glasses, hearing protection, gloves, chainsaw chaps, and sturdy boots.
2. Work Area Safety: Clear work area of obstacles; ensure secure footing; keep bystanders at safe distance.
3. Chain Brake: Test function before each use; engage when carrying or moving short distances.
4. Kickback Awareness: Be aware of kickback zone; use reduced-kickback chain; maintain proper grip.

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

Assembly & Preparation

Assemble chainsaw following these steps.

1. Attach Guide Bar & Chain: Place bar on studs; align chain with drive sprocket; ensure cutting teeth face forward on top of bar.
2. Tension Chain: Use side-access tensioner to adjust until chain snaps back when pulled from bar.
3. Fill Fuel: Use STIHL MotoMix® or 50:1 fuel/oil mixture (89 octane minimum).
4. Fill Chain Oil: Use STIHL chain oil or equivalent; check flow before operation.
5. Check Controls: Ensure throttle trigger, throttle lockout, and chain brake function properly.

CAUTION! Fuel is flammable. Refuel in well-ventilated area with engine off and cool. Wipe spills immediately.

Specifications

• Engine Type: 2-stroke, single cylinder, air-cooled.
• Ignition System: STIHL Electronic Ignition (CDI).
• Carburetor: Diaphragm-type with fuel pump.
• Fuel/Oil Ratio: 50:1 (STIHL HP Ultra or equivalent).
• Idle Speed: 2,800 rpm.
• Maximum Power Speed: 13,000 rpm.
• Sound Pressure Level: 106 dB(A).
• Vibration Levels: Front handle: 4.2 m/s²; Rear handle: 5.8 m/s².
• Warranty: Limited warranty for private users (see separate warranty card).

Controls and Components

Main components: Front handle with throttle trigger, rear handle, master control lever, chain brake lever, decompression valve, fuel/oil caps, chain tensioner.

Master Control Lever: Controls choke (cold start), run position, and stop position.

Chain Brake: Manual activation via front hand guard; inertia-activated during kickback.

Throttle Lockout: Must be depressed before throttle trigger can be engaged.

Decompression Valve: Reduces compression for easier starting (press before pulling starter).

Starting & Stopping

Cold Start Procedure:

1. Engage chain brake by pushing hand guard forward.
2. Press decompression valve (if equipped).
3. Set master control lever to choke position (full down).
4. Press throttle lockout and pull throttle trigger once.
5. Place on ground, hold rear handle with right foot.
6. Pull starter rope sharply until engine fires (1-5 pulls).
7. Move master control lever to half-throttle position.
8. Pull starter rope until engine starts.
9. Briefly blip throttle to disengage fast idle.

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

Stopping: Release throttle; move master control to stop position.

Operating Instructions

Proper cutting techniques for safety and efficiency.

1. Grip: Hold front handle with left hand, rear handle with right hand. Thumbs wrapped underneath.
2. Stance: Feet shoulder-width apart, balanced position.
3. Starting Cut: Apply light pressure; let chain do the work.
4. Buckling: Support log properly; cut from top down; watch for binding.
5. Limbing: Stand on left side of trunk; cut downward branches first.
6. Felling: Not recommended for inexperienced users. Consult professional for tree felling.

Tip: Maintain sharp chain; proper lubrication reduces wear and improves cutting.

Maintenance Schedule

Interval	Task
Daily	Check chain tension, sharpness, lubrication; clean air intake; inspect for damage
Weekly	Clean spark arrestor screen; check spark plug; clean exterior
Monthly	Clean fuel filter; check fuel lines; inspect anti-vibration elements
Seasonally	Replace air filter; check clutch drum and sprocket; replace spark plug
Annually	Professional servicing recommended

CAUTION! Always disconnect spark plug wire before performing maintenance.

Chain & Bar Care

Proper chain maintenance ensures optimal performance.

1. Sharpening: Use round file matching chain pitch (typically 3/8" P). Maintain 30° cutting angle.
2. Depth Gauges: File down to proper height (0.025" / 0.65 mm) using depth gauge tool.
3. Bar Maintenance: Clean bar groove regularly; flip bar monthly for even wear.
4. Lubrication: Check oil flow; adjust oiler if necessary (screw near oil cap).

WARNING! Always wear gloves when handling chain. Sharp cutters can cause serious injury.

Storage Guidelines

Proper storage prevents fuel system issues.

1. Short-term (under 30 days): Add fuel stabilizer to fresh fuel; run engine 2 minutes.
2. Long-term: Drain fuel tank completely; run engine until it stops from fuel starvation.
3. Chain: Remove, clean, and soak in oil; store in sealed container.
4. General: Clean entire saw; store in dry, secure location away from children.

CAUTION! Never store with fuel in tank for extended periods. Fuel deterioration can damage carburetor.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No spark/flooded/old fuel	Check spark plug; use fresh fuel; follow starting procedure exactly.
Engine starts then dies	Clogged fuel filter/air filter	Replace fuel filter; clean air filter.
Poor cutting performance	Dull chain/improper lubrication	Sharpen chain; check oil flow; adjust oiler.
Chain won't stop when brake engaged	Worn brake band/clutch	Have dealer inspect brake system.
Excessive vibration	Loose components/worn AV mounts	Tighten all fasteners; replace anti-vibration elements.

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

Support: 1-800-467-8445; www.stihlusa.com