Stihl 042 AV Manual

The Stihl 042 AV is a professional-grade chainsaw featuring anti-vibration technology, a powerful engine, and durable construction for demanding cutting tasks. This manual covers safety instructions, technical specifications, assembly, operation, maintenance, troubleshooting, and storage guidelines to ensure safe and efficient use.

1. Safety Instructions 2. Technical Specifications 3. Assembly & Preparation 4. Controls & Components 5. Starting & Operation 6. Maintenance Schedule 7. Chain & Bar Care 8. Fuel & Lubrication 9. Storage Guidelines 10. Troubleshooting 11. Warranty & Support

Safety Instructions

Always wear appropriate personal protective equipment (PPE): safety glasses, hearing protection, gloves, chainsaw chaps, and sturdy boots. Keep bystanders at a safe distance. Never operate the saw above shoulder height or with one hand.

Hazard	Precaution
Kickback	Hold saw firmly with both hands; use reduced-kickback chain; avoid tip contact.
Fuel handling	Refuel in well-ventilated area with engine off and cool; use approved fuel containers.
Electrical hazards	Keep away from power lines; assume all wires are energized.
Cutting techniques	Plan cuts; be aware of falling branches; maintain secure footing.
Maintenance safety	Disconnect spark plug before servicing; use only Stihl-approved parts.

Technical Specifications

Engine Type: 2-stroke, single cylinder, air-cooled.
Displacement: 61.5 cc.
Power Output: 3.5 kW (4.7 hp).
Fuel Tank Capacity: 0.55 L.
Oil Tank Capacity: 0.26 L.
Guide Bar Lengths: 40 cm (16") to 50 cm (20") recommended.
Chain Pitch: 3/8" or .325".
Weight (powerhead): 6.2 kg (13.7 lbs).
Anti-Vibration System: AV handles with rubber dampeners.
Ignition System: Electronic, capacitor discharge.

Assembly & Preparation

Unpack all components and inspect for damage.

Attach guide bar: Loosen bar nuts, position bar on studs, align chain with drive sprocket, tension chain correctly.
Install chain: Ensure cutting teeth face forward on top of bar; adjust tension.
Fill tanks: Add fuel mix (50:1 gasoline to 2-stroke oil) to fuel tank; fill bar/chain oil reservoir.
Check controls: Verify throttle trigger, throttle lockout, chain brake, and master control lever function.

WARNING! Use only Stihl-approved bar, chain, and lubricants. Incorrect assembly can cause severe injury.

Controls & Components

Front Handle: Includes throttle trigger and throttle lockout. Rear Handle: Contains master control lever (stop switch, choke, fast idle). Chain Brake: Manual activation via front hand guard; inertia-activated. Decompression Valve: Eases starting. Air Filter: Paper element, removable for cleaning. Spark Arrestor: In muffler.

Master Control Lever Positions: STOP (0), RUN (I), CHOKE/START (II).

Starting & Operation

Cold Start:

Engage chain brake. Set master control to choke (II).
Press decompression valve (if equipped).
Place saw on firm ground, hold rear handle with right foot.
Pull starter rope briskly until engine fires.
Move master control to run (I). Pull again to start.
Blip throttle to disengage fast idle.

Warm Start: Master control at run (I); no choke.

Cutting: Apply light pressure; let chain do the work. Avoid pinching bar. Use bucking spikes for leverage.

Maintenance Schedule

Interval	Task
Daily	Clean air filter; check chain tension, sharpness, and lubrication; inspect for loose fasteners.
Every 10 hours	Clean spark arrestor screen; check fuel filter.
Every 20 hours	Replace air filter; inspect spark plug; clean cooling fins.
Every 50 hours	Replace fuel filter; clean carburetor air passage; check anti-vibration elements.
Annually	Professional inspection of piston, cylinder, bearings.

Chain & Bar Care

Sharpening: Use round file matching chain pitch (e.g., 5.5 mm). Maintain correct filing angle (typically 30°). Depth gauges must be filed to proper height (0.65 mm). Tension: Chain should snap back when pulled from bar; adjust when cool. Bar maintenance: Clean groove weekly; flip bar monthly for even wear; dress rails with flat file if burred.

CAUTION! Always wear gloves when handling chain. A dull chain increases kickback risk.

Fuel & Lubrication

Fuel Mix: Use 89 octane unleaded gasoline mixed with Stihl HP Ultra 2-stroke oil at 50:1 ratio. Do not use fuel older than 60 days. Bar & Chain Oil: Use Stihl chainsaw oil or equivalent for high adhesion. Check oiler output: Hold tip near light surface at high RPM; oil line should appear. Adjust oiler screw if needed.

Storage Guidelines

Drain fuel tank and run engine until carburetor is dry.
Remove chain, clean, and soak in oil. Clean bar groove.
Remove spark plug, add teaspoon of oil, pull starter slowly to coat cylinder.
Clean entire saw; store in dry, cool place, covered.

Long-term: Consider professional winterization.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No spark, flooded, stale fuel	Check spark plug; dry plug; use fresh fuel mix.
Engine runs poorly	Clogged air filter, carburetor issues	Clean/replace air filter; adjust carburetor (H/L screws).
Chain doesn't turn	Brake engaged, clutch worn, sprocket damaged	Disengage brake; inspect clutch drum and sprocket.
Excessive vibration	Loose parts, damaged AV mounts	Tighten bolts; inspect anti-vibration elements.
Chain not oiling	Clogged oiler, empty tank, wrong oil	Clean oil passages; fill with proper oil; check pump.

Warranty & Support

Stihl 042 AV includes a limited warranty covering defects in materials and workmanship. Proof of purchase required. Warranty does not cover wear parts (chain, bar, spark plug, filters) or damage from misuse, improper fuel, or lack of maintenance. For service, contact an authorized Stihl dealer. Always use genuine Stihl parts.

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