stihl 025 chainsaw owners manual

The STIHL 025 is a professional-grade gasoline chainsaw designed for demanding cutting tasks. It features a powerful engine, robust construction, and safety systems like the STIHL Quickstop® inertia chain brake. This manual covers essential safety instructions, assembly, operation, maintenance, troubleshooting, and specifications to ensure safe and efficient use.

Safety Warnings & Symbols

Operating a chainsaw is hazardous. Understanding and following all safety instructions is critical to prevent serious injury or death.

Components & Assembly

Unpack and inspect all parts. Assemble the chainsaw on a clean, stable surface before first use.

1. Attach Guide Bar & Chain: Place bar on studs, loop chain over sprocket and onto bar rails with cutters facing forward. Install bar nuts and adjust chain tension.
2. Fill Chain Oil Tank: Use STIHL or approved biodegradable chain oil. Fill to MAX mark.
3. Fuel Mix: Prepare 50:1 gasoline to 2-cycle engine oil mixture (e.g., STIHL HP Ultra).
4. Check Controls: Ensure throttle trigger, throttle trigger lockout, and chain brake function correctly.

WARNING! Never operate the saw without proper chain tension and lubrication. A loose chain can derail and cause severe injury.

Fuel & Lubrication

Using the correct fuel and lubricants is essential for performance and engine longevity.

1. Fuel: Use fresh, unleaded gasoline with a minimum octane rating of 89. Mix with a high-quality 2-cycle engine oil at a 50:1 ratio. Shake container thoroughly.
2. Chain Oil: Use STIHL chain oil or an approved substitute. Check oil level before each use.
3. Filling: Clean area around caps. Fill fuel and oil tanks on level ground. Wipe up any spills immediately.
4. Storage: For storage over 30 days, drain fuel tank and run engine until it stops to purge carburetor.

CAUTION! Gasoline is extremely flammable. No smoking. Fill outdoors, away from ignition sources.

Starting & Operation

• Pre-Start Check: Verify chain tension, lubrication, and that the area is clear of obstacles and people.
• Cold Start: Set master control lever to choke position (⬇). Press decompression valve (if equipped). Pull starter rope sharply until engine fires. Move lever to half-throttle position (⬆). Pull again to start.
• Warm Start: Set master control lever to half-throttle position (⬆). Pull starter rope.
• Cutting Technique: Maintain firm footing. Hold saw firmly with both hands. Let the chain do the work; do not force it. Be aware of kickback. Plan your cut and escape path.
• Chain Brake: Test function regularly. The inertia-activated Quickstop® should engage if kickback occurs.

Chain & Bar Maintenance

Regular maintenance ensures optimal cutting performance and safety.

Chain Sharpening: Use correct round file size (typically 5/32" or 3/16"). Maintain proper filing angle (usually 30°). File all cutters to equal length. Check depth gauges (rakers) with a gauge and file down if necessary.

Chain Tension: Chain should be snug against the bar but pull freely by hand. Re-tension when chain sags (always when cold). A properly tensioned chain will not sag from the bar rails.

Bar Care: Regularly clean bar groove and oil holes. Flip the bar weekly for even wear. Look for signs of wear or "burring" on the rails.

Lubrication Check: Run saw at high idle, pointing chain at a light-colored surface (e.g., stump). A line of oil should be visible, indicating oil is reaching the chain.

Carburetor Adjustment

The STIHL 025 carburetor has three adjustment screws: L (low speed), H (high speed), and LA (idle).

1. Initial Settings: Gently turn L and H screws clockwise until lightly seated, then counterclockwise 1 turn as a baseline.
2. Final Adjustment: Should be performed by a STIHL-trained technician with a tachometer for optimal performance and emissions compliance. Incorrect adjustment can damage the engine.
3. Idle Speed (LA): Adjust so chain does not move when engine is idling. Chain must be stationary.

NOTICE: Tampering with the H and L screws may void the emissions warranty. Refer to an authorized STIHL dealer for adjustment.

Troubleshooting

Storage

Proper storage prevents fuel system issues and corrosion.

1. Clean the entire saw, removing sawdust and resin.
2. Drain the fuel tank completely. Run the engine at idle until it stops to use up fuel in the carburetor.
3. Remove the chain and bar. Clean thoroughly, oil them, and store separately.
4. Store in a dry, secure place, out of reach of children.

CAUTION! Storing with fuel in the carburetor will cause varnish deposits, leading to starting and performance problems.

Technical Specifications

• Engine Displacement: 45.4 cc (2.77 cu. in.)
• Power Output: 2.4 kW (3.2 bhp)
• Fuel/Oil Ratio: 50:1 (STIHL HP Ultra or equivalent)
• Guide Bar Lengths: 16" (40 cm) to 20" (50 cm) recommended
• Chain Pitch/Gauge: .325" / .063" (common)
• Weight (powerhead only): ~5.2 kg (11.5 lbs)
• Sound Pressure Level: ~112 dB(A)
• Vibration Levels (front/rear handle): Complies with relevant standards.

Warranty & Support

STIHL offers a limited warranty for the original purchaser. Warranty details are provided with the product at the time of purchase from an authorized STIHL dealer.

For Service: All repairs and adjustments should be performed by an authorized STIHL servicing dealer.

For Support: Contact your local STIHL dealer or visit the official STIHL website for manuals, parts diagrams, and dealer locator.

Safety & Training: STIHL recommends professional training for chainsaw users. Contact your dealer for information on training opportunities.