Husqvarna 440 Service Manual

The Husqvarna 440 is a professional-grade chainsaw designed for demanding forestry and arborist work. This service manual provides comprehensive information for maintenance, troubleshooting, and repair. It covers the 2-stroke engine, fuel system, ignition, chain brake, cutting equipment, and all major components. Below are key sections for safety, specifications, maintenance procedures, troubleshooting, and parts identification.

1. Features at a Glance 2. Safety Information 3. Specifications 4. Maintenance Schedule 5. Engine Service 6. Fuel System 7. Ignition System 8. Chain & Bar Maintenance 9. Chain Brake System 10. Troubleshooting 11. Parts Diagrams

Features at a Glance

Key components: X-Torq engine for reduced emissions, Air Injection air cleaning system, LowVib anti-vibration, combined choke/stop control, inertia activated chain brake, side-mounted chain tensioner.

Feature	Description
Engine Type	2-stroke, single cylinder, X-Torq
Displacement	40.9 cc
Power Output	2.4 kW (3.2 hp)
Fuel Tank Volume	0.5 liters
Oil Tank Volume	0.26 liters
Recommended Bar Length	13" to 18" (33 cm to 45 cm)
Weight (excl. cutting equipment)	4.9 kg (10.8 lbs)
Ignition System	Electronic, SEM
Chain Brake	Inertia activated
Vibration Dampening	LowVib system

Safety Information

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

Work Area Safety: Keep bystanders and animals at least 15 meters away.
Fuel Safety: Refuel in a well-ventilated area with the engine stopped and cool. Use fuel mix 50:1 (Husqvarna XP+ oil).
Chain Brake: Test function before each use.
Kickback: Be aware of kickback zone (upper quadrant of bar nose).

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

Specifications

Model: Husqvarna 440
Engine Displacement: 40.9 cm³
Cylinder Bore: 40 mm
Piston Stroke: 32.6 mm
Maximum Power Speed: 9600 rpm
Idle Speed: 2700 rpm
Spark Plug: Champion RCJ7Y or equivalent, gap 0.5 mm
Carburetor: Zama C1Q-S199A or Walbro WT-645
Fuel Recommendation: Minimum 90 octane unleaded gasoline mixed with Husqvarna 2-stroke oil at 50:1 ratio.
Chain Pitch: 3/8" or .325"
Chain Gauge: 0.050" (1.3 mm)

Maintenance Schedule

Access daily and periodic maintenance tasks. Front Panel: Chain tension, chain oiler check, air filter cleaning.

Daily: Check chain tension and sharpness, check chain brake function, clean air filter, check for loose nuts/bolts.

Weekly/50 hrs: Clean cooling fins, check spark plug, clean spark arrestor screen (if equipped), clean fuel filter.

Seasonal/100 hrs: Replace fuel filter, clean carburetor, check clutch and sprocket, check anti-vibration mounts.

Engine Service

Cylinder & Piston: Inspect for scoring. Crankshaft seals: Check for leaks. Muffler: Clean regularly. Decompression valve: Check function.

Remove top cover and air filter housing.
Remove cylinder cover and muffler.
Inspect piston through exhaust port.
Use a piston stop to hold crankshaft when removing clutch.

Tip: Use a torque wrench for all critical fasteners. Cylinder base nuts: 10 Nm.

Fuel System

Includes fuel tank, filter, lines, carburetor, and purge bulb.

Fuel Filter: Replace if dirty or clogged. Access through tank filler neck.
Fuel Lines: Check for cracks or leaks. Replace if hardened.
Carburetor Adjustment: Use tachometer. Standard settings: L=1 turn out, H=1 turn out. Idle speed: 2700 rpm.
Carburetor Diaphragms: Inspect for stiffness or tears.

WARNING! Fuel is highly flammable. Work in a well-ventilated area away from sparks or open flame.

Ignition System

Electronic ignition module, spark plug, and stop switch.

Spark Plug: Check gap (0.5 mm). Replace if electrodes are worn or insulator is cracked.
Ignition Module: Check for spark with tester. Air gap between module and flywheel: 0.3 mm.
Stop Switch: Test continuity. Should be open circuit when in RUN position.
Flywheel Key: Check for shearing if engine timing is off.

CAUTION! Do not pull the starter cord with spark plug removed and connected unless testing for spark. Risk of fire.

Chain & Bar Maintenance

Proper chain tension, sharpening, and bar care are critical for performance and safety.

Chain Tension: Correct when snug against bar but can be pulled around by hand. Adjust via side tensioner.

Sharpening: Use correct round file size (typically 4.0 mm for 3/8" chain). Maintain correct filing angle (typically 30°).

Bar Maintenance: Clean bar groove regularly. Flip bar weekly for even wear. Dress bar rails with a flat file if burred.

Chain Brake System

Inspect band for wear. Check handle mechanism for free movement. Test activation by striking front hand guard sharply.

CAUTION! A malfunctioning chain brake can result in serious injury. Do not operate saw if brake does not engage properly.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine will not start	No spark, flooded, fuel issue	Check spark plug, ignition. Check fuel lines, filter, carburetor. Use correct fuel mix.
Engine starts but dies	Clogged fuel filter, carb adjustment	Replace fuel filter. Check carburetor diaphragms and settings.
Lacks power/overheats	Clogged air filter, muffler screen, carb settings	Clean air filter and spark arrestor screen. Adjust carburetor (H needle).
Chain does not oil	Clogged oil passages, faulty pump	Clean bar oil holes and saw's oil outlet. Check oil pump drive and function.
Excessive vibration	Loose parts, worn AV mounts, unbalanced clutch	Tighten all fasteners. Inspect and replace anti-vibration mounts.

Reset: For electronic ignition, no reset function. For carburetor, return adjustment screws to standard settings.

Service: For authorized service, contact Husqvarna dealer. Find parts and manuals at www.husqvarna.com.