The Stihl 045 AV is a professional-grade chainsaw featuring Anti-Vibration (AV) technology, a powerful engine, and durable construction for demanding forestry and cutting applications. This service manual provides comprehensive information for maintenance, troubleshooting, repair, and specifications to ensure optimal performance and safety. Below are key sections covering safety precautions, technical data, maintenance procedures, engine service, fuel system, ignition system, and troubleshooting guides.
Always prioritize safety when servicing the Stihl 045 AV. Disconnect the spark plug before any maintenance. Use proper tools and personal protective equipment (PPE).
| Warning | Description |
|---|---|
| Fuel Handling | Use clean, fresh fuel mix (gasoline & 2-stroke oil). No smoking near fuel. |
| Sharp Chain | Always handle chain with gloves; ensure chain brake is functional. |
| Hot Components | Allow engine to cool before servicing muffler, cylinder, etc. |
| Electrical Safety | Disconnect spark plug wire to prevent accidental starting. |
| Ventilation | Service in well-ventilated area; avoid inhaling exhaust fumes. |
| Proper Tools | Use Stihl-approved or metric tools to avoid damage. |
| Torque Specifications | Adhere to specified torque values for bolts and nuts. |
| Chain Tension | Check and adjust chain tension regularly; loose chain can derail. |
| Bar & Sprocket | Inspect for wear; replace if grooved or damaged. |
| AV Mounts | Check anti-vibration mounts for cracks or deterioration. |
Key technical specifications for the Stihl 045 AV chainsaw.
Regular maintenance ensures longevity and safe operation.
WARNING! Never operate a chainsaw with damaged or missing safety components.
Procedures for engine disassembly, inspection, and reassembly.
Cylinder & Piston: Remove muffler to inspect piston and cylinder for scoring. Use a ring compressor for piston installation. Ensure ring end gaps are correctly spaced.
Crankshaft & Bearings: Check crankshaft runout with dial indicator. Replace main bearings if rough or noisy. Use a puller for bearing removal/installation.
Seals & Gaskets: Replace all seals (crankcase, crankshaft) during overhaul. Use OEM gaskets for proper sealing.
Torque Values (Key Fasteners): Cylinder bolts: 20 Nm (15 ft-lbs). Connecting rod bolts: 10 Nm (7.5 ft-lbs). Clutch: Left-hand thread, tighten securely.
Break-in Procedure: After overhaul, run at varied RPMs (no full load) for first tank of fuel to seat rings.
Maintaining the fuel system is critical for performance.
Tip: Always use fresh, ethanol-free fuel if possible to prevent carburetor varnish.
Electronic ignition system troubleshooting and service.
| Component | Test/Procedure |
|---|---|
| Spark Plug | Use Champion RCJ7Y or equivalent. Gap: 0.5 mm (0.020"). Replace if electrode is worn or fouled. |
| Ignition Coil | Check primary/secondary resistance with multimeter. Primary: ~0.5-2 Ω, Secondary: ~5-15 kΩ. Replace if out of spec or cracked. |
| Stop Switch | Ensure wire is not grounded when in RUN position. Disconnect to test if switch is faulty. |
| Flywheel & Key | Inspect for sheared woodruff key causing timing issues. Torque nut to 40 Nm (30 ft-lbs). |
| Spark Arrestor | Clean screen in muffler with wire brush to prevent overheating and power loss. |
CAUTION! Never crank engine with spark plug removed and wire attached near cylinder—risk of ignition coil damage.
Proper chain and bar care ensures cutting efficiency and safety.
WARNING! A dull chain increases kickback risk and operator fatigue.
The clutch engages the chain at high RPMs.
Clutch Removal: Use clutch tool to hold drum; remove LEFT-HAND thread clutch nut. Inspect clutch shoes for wear, springs for fatigue.
Clutch Drum & Bearing: Check drum for groove from chain; replace if deep. Lubricate needle bearing behind drum.
Drive Sprocket: Replace if teeth are hooked or worn. Rim-type sprockets are easier to replace than spur sprockets.
Oil Pump: Manual or automatic oiler. Check worm gear on crankshaft that drives pump. Clean oil pickup filter in tank.
The AV system reduces operator fatigue by isolating handles from engine vibrations.
AV Mounts: Four rubber mounts connect engine to frame/handles. Inspect for cracks, tears, or deterioration.
Replacement: Remove handle assembly; press out old mounts, press in new ones. Use silicone grease to ease installation.
Handle Alignment: Ensure handles are aligned correctly after mount replacement to prevent control issues.
WARNING! Operating with failed AV mounts increases vibration and can lead to handle failure.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Engine won't start | No spark, flooded, fuel issue | Check spark, plug condition. Dry plug if flooded. Verify fuel flow, carburetor settings. |
| Engine starts then dies | Clogged fuel filter, carburetor, air leak | Replace fuel filter. Clean carburetor. Pressure test crankcase for leaks. |
| Lacks power/overheats | Dirty air filter, clogged spark arrestor, carb adjustment | Clean/replace air filter. Clean spark arrestor. Adjust carburetor (H & L). |
| Chain doesn't turn | Clutch worn, brake engaged, sprocket | Inspect clutch shoes/springs. Disengage chain brake. Check sprocket wear. |
| Excessive vibration | Failed AV mounts, unbalanced chain, loose parts | Replace AV mounts. Sharpen/balance chain. Tighten all fasteners. |
| Oil not lubricating chain | Clogged oil passages, worn pump, wrong oil | Clean oil ports. Check oil pump worm gear. Use correct chain oil. |
| Chain throws or derails | Loose chain, worn bar, damaged drive links | Adjust tension. Inspect bar for wear/burrs. Replace damaged chain. |
Reset: For electronic issues (if equipped), disconnect spark plug wire for 30 seconds to reset module.
Service: For technical support or genuine parts, contact authorized Stihl dealer or visit www.stihlusa.com.
Use exploded-view diagrams for part identification and ordering.
Ordering: Always use genuine Stihl parts for fit and performance. Provide model (045 AV) and serial number when ordering.