Stihl Chainsaw 250 Manual

The Stihl Chainsaw 250 is a professional-grade gasoline-powered chainsaw designed for demanding cutting tasks. It features a powerful engine, anti-vibration system, quick-stop chain brake, and ergonomic design for user comfort and safety. Below are key sections covering safety, features, assembly, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Engine with decompression valve, anti-vibration system, QuickStop® inertia-activated chain brake, side-access chain tensioner, and ErgoStart™ easy-start system.

Feature	Description
Engine Displacement	45.4 cc two-stroke engine
Guide Bar Length	16-inch (40 cm) standard
Chain Pitch	3/8" PMM3
Fuel Tank Capacity	0.53 US pt (0.25 l)
Oil Tank Capacity	0.26 US pt (0.12 l)
Weight (powerhead)	10.1 lbs (4.6 kg)
Anti-Vibration System	Reduces operator fatigue
Chain Brake	QuickStop® inertia-activated for safety
Starting System	ErgoStart™ for easier pulls
Decompression Valve	Reduces starting effort

Safety Instructions

Read all instructions before operation. Always wear protective equipment.

1. Personal Protective Equipment (PPE): Wear safety glasses, hearing protection, gloves, chainsaw chaps, and steel-toe boots.
2. Work Area Safety: Clear area of obstacles; ensure secure footing; keep bystanders away.
3. Fuel Safety: Refuel in well-ventilated area with engine off and cool. Use proper fuel/oil mix.
4. Kickback Awareness: Hold saw firmly; avoid contact with bar tip; use reduced-kickback chain.

WARNING! Chainsaws are dangerous. Failure to follow safety rules can result in serious injury or death.

Assembly & Preparation

Unpack and inspect contents. Assemble guide bar and chain.

1. Attach Guide Bar: Remove bar cover nuts, position bar over studs, align chain drive links with sprocket.
2. Install Chain: Place chain over bar, ensuring cutting teeth face forward on top of bar.
3. Tension Chain: Use side-access tensioner to adjust until chain snaps back when pulled from bar.
4. Fill Tanks: Add fuel mix (50:1 gasoline to 2-cycle oil) to fuel tank. Fill bar/chain oil tank with recommended oil.

CAUTION! Ensure chain is properly tensioned and moves freely before starting.

Specifications

• Engine Type: 2-stroke single cylinder gasoline engine.
• Power Output: 2.6 kW (3.5 bhp).
• Idle Speed: 2,800 rpm.
• Maximum Power Speed: 9,500 rpm.
• Fuel/Oil Mix: 50:1 (ISO-L-EGD or JASO FD certified oil).
• Ignition System: Electronic, capacitor discharge.
• Spark Plug: Bosch WSR 6 F or equivalent.
• Sound Pressure Level: 106 dB(A).
• Vibration Level (front/rear handle): 4.2/2.5 m/s².

Controls and Components

Main controls located on rear handle and body. Front Handle: Hand guard with chain brake lever. Rear Handle: Throttle trigger, throttle trigger lockout, stop switch. Side Panel: Master control lever (start/choke/run), decompression valve, fuel primer bulb.

Additional Features: Chain catcher, right-hand guard, muffler with spark arrestor, side-access chain tensioner, adjustable automatic oiler.

Operation: Master control lever settings: STOP (0), START (choke position), RUN (normal operation). Throttle trigger lockout must be depressed before throttle can be engaged.

Starting the Engine

Cold Start Procedure (with decompression valve):

1. Engage chain brake by pushing hand guard forward.
2. Set master control lever to START (choke) position.
3. Press decompression valve (if equipped).
4. Press fuel primer bulb 5-6 times until fuel is visible.
5. Place saw on ground, hold rear handle with right foot.
6. Pull starter handle slowly until resistance is felt, then pull briskly.
7. After engine fires, move master control lever to RUN position.
8. Pull starter handle again to start engine.

Tip: For warm start, set master control lever directly to RUN position.

Operating Instructions

Proper cutting techniques for safety and efficiency.

1. Basic Stance: Stand with feet shoulder-width apart, left foot slightly forward.
2. Grip: Hold front handle with left hand, rear handle with right hand. Thumb wrapped under handle.
3. Starting Cut: Apply slight pressure with bumper spikes against wood. Open throttle fully before engaging wood.
4. Cutting: Let chain do the work; avoid forcing saw. Be aware of pinch points.
5. Kickback Prevention: Never cut with bar tip. Maintain firm grip. Use reduced-kickback chain and bar.
6. Chain Brake Test: Regularly test by pushing hand guard forward with engine off.

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

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

Interval	Task
Before each use	Check chain tension, sharpness, and lubrication
Daily	Clean air filter, check for loose fasteners
Weekly	Clean spark arrestor screen, check spark plug
Monthly	Clean cooling fins, check fuel filter
Seasonally	Replace spark plug, clean carburetor
Annually	Professional servicing recommended

Chain Sharpening & Tensioning

Proper chain maintenance is critical for performance and safety.

1. Sharpening: Use round file matching chain pitch (typically 5/32" or 4.0mm). Maintain 30° filing angle. File each cutter equally.
2. Depth Gauge: Check and file depth gauges with flat file when sharpening. Maintain 0.025" (0.65mm) below cutter top plate.
3. Tensioning: Chain should be snug against bar but pull freely. Adjust when chain is cool. Proper tension: chain should snap back when pulled from bar.
4. Lubrication: Ensure oiler is working. Chain should throw oil during operation. Adjust oiler screw if needed.

CAUTION! Always wear gloves when handling chain. Ensure saw is off and cool.

Storage Guidelines

Proper storage prevents fuel system issues and corrosion.

1. Short-term (under 30 days): Add fuel stabilizer to fuel mix and run engine for 2 minutes.
2. Long-term: Drain fuel tank completely. Run engine until it stops to clear carburetor. Remove chain, clean and oil it. Store in dry place.
3. Bar Maintenance: Clean bar groove and oil holes. Hang bar or store flat to prevent warping.

WARNING! Never store chainsaw with fuel in tank for extended periods without stabilizer.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No spark, fuel issues, flooded	Check spark plug; ensure fuel mix fresh; wait if flooded; check air filter.
Engine starts then dies	Fuel filter clogged, carburetor issues	Replace fuel filter; clean carburetor; check fuel lines.
Poor cutting performance	Dull chain, improper tension	Sharpen chain; adjust tension; check bar groove.
Chain won't oil	Empty oil tank, clogged oiler	Fill oil tank; clean oil holes in bar; check oil pump.
Excessive vibration	Loose components, damaged AV mounts	Tighten all fasteners; check anti-vibration mounts.
Chain brake not engaging	Dirty mechanism, worn parts	Clean brake band and mechanism; replace if worn.

Service: For technical support or parts, contact authorized Stihl dealer or visit www.stihlusa.com.

Safety Recall Check: Verify your model hasn't been recalled at official Stihl website.