Husqvarna 440 Repair Manual

The Husqvarna 440 is a professional-grade chainsaw designed for demanding forestry and arborist work. This repair manual provides comprehensive instructions for maintenance, troubleshooting, and repair of the Husqvarna 440 chainsaw, covering the engine, fuel system, ignition, chain brake, cutting equipment, and electrical system. Below are key sections for safety, specifications, maintenance procedures, troubleshooting, and parts identification.

Features at a Glance

Key components: X-Torq engine for reduced emissions, Air Injection cleaning system, LowVib anti-vibration, Smart Start for easy starting, combined choke/stop control, inertia-activated chain brake.

Safety Information

Always wear appropriate Personal Protective Equipment (PPE) including safety helmet, hearing protection, eye protection, gloves, chainsaw protection trousers, and safety boots.

1. Work Area Safety: Keep bystanders and animals at least 15 meters away. Ensure secure footing.
2. Fuel Safety: Refuel outdoors only when engine is cold. Use fuel mix (50:1 Husqvarna XP+ oil).
3. Chain Safety: Ensure chain brake functions correctly. Always engage chain brake when not cutting.
4. Kickback Zone: Avoid contact with the upper quadrant of the bar tip.

WARNING! A chainsaw is a dangerous tool. Improper use can cause serious injury or death. Read and understand the operator's manual before use.

Specifications

• Model: Husqvarna 440.
• Engine Displacement: 40.9 cc.
• Power Output: 2.2 kW at 9000 rpm.
• Maximum Power Speed: 9000 rpm.
• Idle Speed: 2700 rpm.
• Fuel Consumption: Approx. 470 g/kWh.
• Sound Pressure Level (LpA): 106 dB(A).
• Sound Power Level (LWA): 121 dB(A).
• Vibration Level (Front/Rear Handle): 3.5/2.5 m/s².
• Spark Plug: NGK BPMR7A (gapped to 0.5 mm / 0.020").

Maintenance Schedule

Access maintenance points via removal of covers and air filter. Daily checks before operation.

Daily: Check chain tension, sharpness, and lubrication. Check all nuts and bolts for tightness. Clean air filter. Check throttle trigger, throttle lockout, and stop switch function.

Weekly (or every 10 hours): Clean cooling fins and cylinder cover. Check spark plug condition and gap. Clean fuel filter in tank. Check carburetor settings.

Monthly (or every 50 hours): Clean spark arrestor screen in muffler. Check fuel line for cracks. Check anti-vibration elements. Check clutch and clutch drum for wear.

Annually (or every 100 hours): Replace fuel filter. Check ignition system (air gap). Clean carburetor. Check all safety functions.

Engine Repair

Cylinder and Piston: Remove muffler, cylinder cover, and cylinder. Inspress for scoring. Piston ring end gap: 0.3-0.5 mm. Crankshaft: Check bearings and seals for wear. Connecting rod side play: max 0.5 mm.

1. Disconnect spark plug cap and fuel line.
2. Remove starter assembly, clutch, and cylinder cover.
3. Remove cylinder bolts and lift off cylinder.
4. Replace piston if rings are worn or piston is scored.
5. Reassemble with new gaskets, torque cylinder bolts to 10 Nm (7.4 ft-lbs).

Tip: Use a piston stop tool to hold crankshaft when removing clutch.

Fuel System

Components: Fuel tank, fuel line, fuel filter, carburetor (Zama C1Q-S267).

1. Carburetor Adjustment: Idle speed screw (T), Low speed screw (L), High speed screw (H). Factory setting: L=1 turn out, H=1 turn out.
2. Fuel Line Replacement: Drain tank, remove old line, install new line with filter.
3. Fuel Filter: Replace annually or if clogged.
4. Fuel Cap: Ensure vent is clear.

WARNING! Use only Husqvarna XP+ 2-stroke oil or equivalent high-quality oil at 50:1 mix ratio with unleaded gasoline (min 90 octane).

Ignition System

Electronic ignition module (SEM). Spark plug: NGK BPMR7A, gap 0.5 mm.

1. Testing Spark: Remove spark plug, connect to cap, ground against cylinder, pull starter. Look for strong blue spark.
2. Ignition Module Air Gap: Set to 0.3 mm (0.012") using feeler gauge between flywheel magnet and module.
3. Stop Switch: Check for continuity. Disconnect wire to test if spark returns.
4. Flywheel Key: Check for shearing if timing is off.

CAUTION! Never run engine without spark plug connected to cap and grounded, as it can damage the ignition module.

Chain & Bar Maintenance

Supports guide bars 13" to 18". Chain types: Husqvarna H30, H32, or equivalent.

1. Chain Tension: Adjust so chain snaps back when pulled from bar. Tighten bar nuts after adjustment.
2. Sharpening: Use round file (4.0 mm for 3/8" chain, 4.8 mm for .325"). Maintain 30° cutting angle, 10° top plate filing angle.
3. Bar Maintenance: Clean bar groove. Flip bar regularly for even wear. Dress rails with flat file if burred.
4. Drive Sprocket: Check for wear (replace if teeth are hooked).
5. Oil Pump: Check output. Adjust screw for flow rate if adjustable.

WARNING! Always stop engine and engage chain brake before performing chain maintenance.

Electrical System

Components: Ignition module, stop switch, spark plug, wiring harness.

Troubleshooting

Reset: For electronic issues, disconnect spark plug cap for 1 minute to reset module.

Service: For genuine Husqvarna parts and service, contact an authorized Husqvarna dealer.

Parts Diagrams

Refer to official Husqvarna 440 IPL (Illustrated Parts List) for exploded views and part numbers for: Cylinder Group, Crankcase, Fuel System, Ignition System, Clutch & Chain Brake, Handle & AV System, Outer Covers.

Common Part Numbers:
Air Filter: 503 87 96-01
Spark Plug: 501 84 77-01 (NGK BPMR7A)
Fuel Filter: 501 87 75-01
Chain Brake Band: 537 00 47-01
Clutch Drum: 501 84 83-01
Anti-Vibration Mount Set: 537 23 40-01