stihl 051 av manual pdf

The STIHL 051 AV is a professional-grade gasoline-powered chainsaw featuring Anti-Vibration (AV) technology, a robust engine, and a range of safety and performance features designed for demanding forestry and cutting tasks. This manual covers essential information for safe operation, maintenance, troubleshooting, and specifications to ensure optimal performance and longevity of your chainsaw.

1. Features at a Glance 2. Safety Instructions 3. Assembly & First-Time Setup 4. Technical Specifications 5. Controls & Components 6. Fuel & Lubrication 7. Starting & Operation 8. Maintenance Schedule 9. Chain & Bar Care 10. Storage Guidelines 11. Troubleshooting

Features at a Glance

Key components: Engine with electronic ignition, Anti-Vibration system, Quickstop chain brake, side-access chain tensioner, and ergonomic handles.

FeatureDescription
Engine TypeTwo-stroke, single-cylinder gasoline engine
DisplacementApprox. 85.4 cc (5.2 cu. in.)
Power OutputHigh torque for demanding cuts
Anti-Vibration System (AV)Reduces operator fatigue
Chain Brake (Quickstop)Safety feature to stop chain in kickback events
Chain TensionerSide-mounted for easy adjustment
Fuel Tank CapacityApprox. 0.95 liters (0.25 US gal)
Oil Tank CapacityApprox. 0.35 liters (0.09 US gal)
Guide Bar LengthsTypically 16" to 24" (40 cm to 60 cm)
Ignition SystemElectronic (CDI)

Safety Instructions

Read and understand all safety warnings before operation. Always wear appropriate PPE.

  1. Personal Protective Equipment (PPE): Always wear safety glasses, hearing protection, gloves, chainsaw chaps/pants, and sturdy boots.
  2. Work Area Safety: Keep bystanders and pets at a safe distance. Ensure secure footing and be aware of your surroundings.
  3. Chain Brake Check: Verify the chain brake functions correctly before each use.
  4. Fuel Safety: Refuel in a well-ventilated area with the engine off and cool. Use only approved gasoline/oil mix.

WARNING! Failure to follow safety instructions can result in serious injury or death. The chain brake is not a substitute for safe operating practices.

Assembly & First-Time Setup

Unpack all components. Assemble guide bar and chain before first use.

  1. Attach Guide Bar & Chain: Place bar on studs, loop chain onto sprocket and bar groove. Adjust tension.
  2. Fill Fuel & Oil: Use fresh fuel mix (50:1 STIHL HP Ultra oil) in fuel tank. Fill bar/chain oil reservoir.
  3. Check Controls: Ensure throttle trigger, throttle lockout, and chain brake move freely.
  4. Initial Start: Follow cold-start procedure. Allow engine to warm up at idle before cutting.

CAUTION! Ensure chain is properly tensioned—a loose chain can derail; an overtightened chain can damage the engine.

Technical Specifications

Controls & Components

Familiarize yourself with all controls before starting the engine.

Main Controls: Throttle trigger, throttle lockout (must be depressed to engage throttle), Master Control lever (combines choke/run/stop functions), Chain brake lever/hand guard, Decompression valve (if equipped), Fuel primer bulb (if equipped).

Components: Muffler with spark arrestor, Air filter cover, Chain tensioner screw, Front hand guard, Rear handle with anti-vibration elements, Fuel and oil caps.

Fuel & Lubrication

Use only high-quality, fresh fuel and recommended lubricants.

  1. Fuel Mix: Unleaded gasoline (min. 89 octane) mixed 50:1 with STIHL HP Ultra 2-stroke oil. Do not use automotive oil or old fuel.
  2. Bar & Chain Oil: Use STIHL chain oil or a quality substitute with good adhesion properties. Check oil flow before cutting.
  3. Refueling: Stop engine. Clean area around caps. Fill carefully to avoid spillage. Tighten caps securely.

Tip: Shake fuel mix container well before refueling. Never store fuel mix in the saw for more than 30 days.

Starting & Operation

Follow correct starting procedure to avoid flooding and ensure safe operation.

  1. Cold Start: Engage chain brake. Set Master Control to choke (full down). Press decomp valve (if equipped). Pull starter cord sharply until engine fires. Move Master Control to half-throttle position (mid). Pull again to start. Briefly blip throttle to disengage choke.
  2. Warm Start: Master Control in run position (horizontal). Pull starter cord.
  3. Cutting Technique: Use full throttle when cutting. Let chain do the work; do not force. Be aware of kickback zone (upper quadrant of bar tip).
  4. Stopping: Release throttle, allow engine to idle. Move Master Control to STOP position.

WARNING! Always engage the chain brake when starting, carrying, or when not actively cutting. Never drop-start the saw.

Maintenance Schedule

Regular maintenance is crucial for safety and performance.

IntervalTask
Before each useCheck chain tension, sharpness, and brake function. Check fuel/oil levels.
DailyClean air filter. Check for loose nuts/bolts. Clean saw exterior.
Weekly (or 5 hrs)Clean spark arrestor screen (if equipped). Inspect guide bar for wear.
Monthly (or 20 hrs)Clean cooling fins. Check fuel filter. Inspect anti-vibration elements.
AnnuallyHave carburetor adjustment and compression checked by a STIHL dealer.

Chain & Bar Care

Proper chain and bar maintenance ensures efficient cutting and long life.

  1. Sharpening: Use correct round file size. Maintain correct filing angle (typically 30°). File all cutters evenly.
  2. Tensioning: Chain should be snug against bar but pull freely by hand. Re-tension when chain is warm after initial use.
  3. Bar Maintenance: Regularly clean bar groove and oil holes. Flip bar weekly to ensure even wear.
  4. Depth Gauges: File down depth gauges (rakers) periodically with a flat file and gauge tool.

CAUTION! A dull or improperly tensioned chain increases kickback risk and operator fatigue.

Storage Guidelines

Prepare the saw properly for short or long-term storage.

  1. Short-term (under 30 days): Run engine dry of fuel mix, or add fuel stabilizer. Store in a dry, secure place.
  2. Long-term: Drain all fuel from tank and carburetor. Run engine until it stops. Remove, clean, and oil the chain. Store chain and bar separately. Clean entire saw.

WARNING! Never store the saw with fuel in the tank in a confined, hot, or poorly ventilated area due to fire and fume hazards.

Troubleshooting

SymptomPossible CauseCorrective Action
Engine will not startNo spark, flooded, old fuel, clogged filterCheck spark plug. Use fresh fuel mix. Clean air filter. Follow correct starting procedure.
Engine runs but dies under loadClogged fuel filter, dirty air filter, carburetor adjustmentReplace fuel filter. Clean air filter. Consult dealer for carb adjustment.
Excessive vibrationLoose components, worn AV buffers, unbalanced chainTighten all bolts. Inspect AV mounts. Check chain sharpness and balance.
Chain does not oilEmpty oil tank, clogged oil holes, faulty oil pumpFill tank. Clean bar oil holes. Check oil line. Consult dealer for pump service.
Chain throws off barLoose chain, worn bar, damaged drive sprocketTension chain properly. Inspect bar for wear. Replace sprocket if worn.

Service: For major repairs or carburetor adjustment, contact an authorized STIHL servicing dealer. Use only genuine STIHL parts.

Support: For additional information, visit www.stihlusa.com or contact your local STIHL dealer.

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