Stihl 025 C Manual

The Stihl 025 C is a professional-grade gasoline-powered chainsaw designed for demanding cutting tasks. It features a reliable two-stroke engine, anti-vibration system, QuickStop chain brake, STIHL Ematic lubrication system, and ergonomic design for user comfort and safety. Below are key sections covering safety, features, operation, maintenance, troubleshooting, and specifications.

Features at a Glance

Key components: Two-stroke engine, anti-vibration handles, QuickStop chain brake, side-access chain tensioner, STIHL Ematic lubrication system, and decompression valve.

Feature	Description
Engine Displacement	45.4 cc two-stroke engine
Power Output	2.6 kW (3.5 hp)
Guide Bar Length	Typically 16" or 18" (40-45 cm)
Chain Brake	QuickStop inertia-activated safety brake
Anti-Vibration	Reduced vibration system for user comfort
Fuel System	Diaphragm carburetor with manual choke
Lubrication	STIHL Ematic automatic oiling system
Starter	STIHL ErgoStart easy-pull mechanism
Weight	Approximately 5.4 kg (11.9 lbs) without bar & chain
Ignition	Electronic ignition (CDI)

Safety Information

Read and understand all safety instructions before operation.

1. Personal Protective Equipment (PPE): Always wear chainsaw chaps, safety glasses, hearing protection, gloves, and steel-toed boots.
2. Work Area Safety: Clear area of bystanders, especially children. Ensure secure footing.
3. Chain Brake: Test before each use. Engage when carrying or moving between cuts.
4. Kickback Awareness: Be aware of kickback zone (upper quadrant of bar tip). Use reduced-kickback chain.
5. Fuel Safety: Refuel in well-ventilated area, away from ignition sources. Use approved fuel mix.

WARNING! Failure to follow safety instructions can result in serious injury or death. Never operate a chainsaw while fatigued or under the influence.

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. Fuel Mix: Use high-quality 2-stroke oil mixed with unleaded gasoline at 50:1 ratio (STIHL HP Ultra recommended).
5. Fill Tanks: Add fuel to fuel tank and chain oil to oil reservoir (STIHL chain oil recommended).

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

Specifications

• Engine Type: Single cylinder, two-stroke, air-cooled.
• Displacement: 45.4 cc.
• Power Output: 2.6 kW (3.5 hp).
• Maximum Engine Speed: 13,500 rpm.
• Idle Speed: 2,800 rpm.
• Fuel Tank Capacity: 0.55 liters (18.6 fl oz).
• Oil Tank Capacity: 0.26 liters (8.8 fl oz).
• Sound Pressure Level: 106 dB(A).
• Vibration Levels: Left handle 4.5 m/s², right handle 5.5 m/s².
• Ignition System: Electronic CDI.
• Spark Plug: Bosch WSR 6 F or equivalent.

Controls and Components

Main controls: Master Control Lever (combines choke, throttle lock, stop switch), throttle trigger, chain brake lever, decompression valve, fuel primer bulb.

Right Side: Throttle trigger, throttle lockout, chain brake lever (front handle), master control lever. Left Side: Decompression valve (if equipped), side-access chain tensioner. Rear: Fuel and oil caps, primer bulb, starter grip.

Master Control Positions: STOP (0), RUN (I), START/CHOKE (II). Chain Brake: Push forward to engage, pull back toward handle to disengage.

Starting & Stopping

Cold Start Procedure:

1. Engage chain brake by pushing lever forward.
2. Press decompression valve (if equipped).
3. Set master control lever to START/CHOKE position (II).
4. Press fuel primer bulb 5-10 times until fuel is visible.
5. Place saw on firm ground, hold rear handle with right foot, pull starter cord slowly until resistance felt, then pull briskly.
6. After engine fires, move master control to RUN (I) position.
7. Pull starter cord again until engine starts.
8. Briefly blip throttle to disengage fast idle.

Warm Start: Master control in RUN (I) position, no choke needed.

Stopping: Move master control lever to STOP (0) position.

Operation & Cutting Techniques

Basic Cutting:

1. Disengage chain brake by pulling lever back toward handle.
2. Hold saw firmly with both hands, right thumb under handle.
3. Use full throttle before contacting wood.
4. Let saw do the work; avoid forcing.
5. For felling: Use proper notch and back cut techniques.
6. For limbing: Work from trunk outward, keep saw stable.
7. For bucking: Support logs properly, cut from top side when possible.

Kickback Prevention: Maintain secure grip, do not cut with bar tip, keep chain sharp and properly tensioned.

Maintenance Schedule

Interval	Task
Daily/Before Use	Check chain tension, sharpness, brake function; clean air filter; check fuel/oil levels
Every 10 Hours	Clean spark arrestor screen; check spark plug
Every 20 Hours	Clean cooling fins; check fuel filter
Every 50 Hours	Replace spark plug; clean carburetor air passage
Every 100 Hours	Check cylinder/piston; replace fuel filter
Annually	Professional servicing recommended

Note: Maintenance intervals may vary based on operating conditions.

Chain Sharpening & Tensioning

Sharpening:

1. Secure bar in vise or use filing guide.
2. Use round file matching chain pitch (typically 3/8" or .325").
3. File at 30° angle, maintaining cutter height consistency.
4. File depth gauges with flat file to proper height (0.025" below cutter edge).

Tensioning:

1. Loosen bar nuts with combination wrench.
2. Turn tensioning screw clockwise until chain fits snugly against bar.
3. Chain should snap back when pulled from bar.
4. Retighten bar nuts while lifting bar tip.

CAUTION! Always wear gloves when handling chain.

Storage Guidelines

Long-term Storage (over 30 days):

1. Drain fuel tank and run engine until it stops.
2. Remove spark plug, add 1 teaspoon of oil to cylinder, pull starter 2-3 times, reinstall plug.
3. Clean entire saw, especially cooling fins and air filter.
4. Remove chain, clean and soak in oil; store separately.
5. Store in dry, dust-free location, away from children.

WARNING! Never store with fuel in tank for extended periods.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No spark, fuel issues, flooded	Check spark plug, fuel mix, air filter; use correct starting procedure
Engine runs poorly	Dirty air filter, carburetor adjustment, fuel filter	Clean/replace air filter; adjust carburetor; replace fuel filter
Chain doesn't turn	Brake engaged, clutch issues, chain jammed	Disengage brake; check clutch springs; clear jam
Excessive vibration	Loose components, unbalanced chain	Tighten all fasteners; check chain condition
Chain oil not flowing	Empty oil tank, clogged oil passages, wrong oil	Fill tank; clean oil ports; use recommended oil
Overheating	Dirty cooling fins, lean fuel mix, dull chain	Clean fins; use proper mix; sharpen chain

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

STIHL Support: Visit www.stihlusa.com or contact 1-800-467-8445 for dealer locations and technical support.