Husqvarna 42 Chainsaw Repair Manual

The Husqvarna 42 is a lightweight, professional-grade chainsaw designed for demanding forestry and arborist work. This manual provides comprehensive repair, maintenance, and troubleshooting information for the Husqvarna 42 model, covering the engine, cutting equipment, fuel system, ignition, carburetor, and safety systems. Below are key sections for safety, specifications, disassembly, troubleshooting, and maintenance procedures.

1. Features at a Glance 2. Safety Information 3. Technical Specifications 4. Maintenance Schedule 5. Engine Repair 6. Fuel System & Carburetor 7. Ignition System 8. Chain & Bar Maintenance 9. Troubleshooting 10. Parts List & Diagrams 11. Warranty & Support

Features at a Glance

Key components: X-Torq engine technology, Air Injection centrifugal air cleaning, Combined choke/stop control, Smart Start, LowVib anti-vibration system, Quick-release air filter, Side-mounted chain tensioner.

Feature	Description
X-Torq Engine	Reduces fuel consumption and exhaust emissions
Air Injection	Centrifugal air cleaning system for longer filter life
Smart Start	Reduces resistance in starter cord for easy starting
LowVib System	Reduces vibration to operator's hands
Quick-release air filter	Easy access for cleaning without tools
Side-mounted chain tensioner	Allows chain adjustment from the side
Combined choke/stop control	Simplified starting procedure
Chain brake	Inertia-activated safety feature
Right-hand guard	Protects against rear kickback
Fuel pump	Automatically feeds fuel to carburetor

Safety Information

Always wear appropriate PPE: helmet, eye protection, hearing protection, gloves, chainsaw chaps, and steel-toed boots.

Pre-operation check: Verify chain brake, throttle lock, chain tension, and sharpness.
Fuel handling: Use fresh fuel mix (50:1 Husqvarna 2-stroke oil); refuel in well-ventilated area away from ignition sources.
Starting: Place on flat ground, engage chain brake, use proper starting procedure.
Operation: Maintain secure footing, be aware of kickback zone, never cut above shoulder height.

WARNING! Failure to follow safety instructions can result in serious injury or death. Always refer to the operator's manual before use.

Technical Specifications

Engine Type: 2-stroke, single cylinder, air-cooled.
Displacement: 40.9 cc (2.5 cu in).
Power Output: 1.8 kW (2.4 hp).
Fuel Tank Volume: 0.5 L (16.9 fl oz).
Oil Tank Volume: 0.25 L (8.5 fl oz).
Bar Length Options: 13", 15", 16".
Chain Pitch: 3/8" LP (Low Profile).
Chain Gauge: 0.050".
Weight (without cutting equipment): 4.4 kg (9.7 lbs).
Sound Pressure Level: 104 dB(A).
Vibration Levels: Front handle 3.2 m/s², Rear handle 4.5 m/s².

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

Interval	Task
Daily	Check chain tension, sharpness, and lubrication; Clean air filter; Inspect for loose parts
Weekly	Clean cooling fins; Check spark plug condition; Clean fuel filter
Monthly	Clean carburetor air intake; Check fuel lines for cracks; Inspect anti-vibration elements
Every 3 months	Replace spark plug; Clean exhaust port and spark arrestor screen
Every 6 months	Replace fuel filter; Check clutch and sprocket wear
Annually	Check cylinder compression; Inspect piston through exhaust port

Note: Service intervals may vary based on usage conditions.

Engine Repair

Disassembly requires proper tools and mechanical knowledge.

Cylinder and Piston: Remove muffler, cylinder cover, and cylinder bolts. Inspect for scoring, replace piston rings if worn.
Crankshaft and Bearings: Requires splitting crankcase. Check bearings for smooth rotation, replace if rough.
Clutch and Sprocket: Remove clutch with special tool, inspect drum for wear, replace sprocket if teeth are hooked.
Ignition System: Check flywheel key, coil air gap (0.3 mm), and spark with tester.

CAUTION! Engine components are precision parts. Clean work area and use torque specifications during reassembly.

Fuel System & Carburetor

Husqvarna 42 uses Zama C1Q-S carburetor with H, L, and T adjustment screws.

Fuel Lines: Replace if cracked or hardened. Route correctly to avoid kinks.
Fuel Filter: Replace annually or if clogged.
Carburetor Adjustment: Initial settings: H - 1 turn out, L - 1 turn out. Fine-tune for optimal performance.
Diaphragms: Check fuel pump and metering diaphragms for stiffness or tears.
Needle Valve: Ensure free movement and clean seat.

Tip: Use pressurized air to clean carburetor passages, never wire or sharp objects.

Ignition System

Electronic ignition system with fixed timing.

Spark Plug: NGK BPMR7A, gap 0.5 mm. Replace if electrode worn or insulator cracked.
Ignition Coil: Check primary resistance (approx. 0.2-0.3 Ω) and secondary resistance (approx. 4-6 kΩ).
Flywheel: Check key for shearing, ensure tight mounting (40 Nm torque).
Stop Switch: Test continuity; should be open when off, closed when on.
Spark Test: Hold plug against cylinder, pull starter - should see strong blue spark.

WARNING! High voltage present. Keep hands clear when testing spark.

Chain & Bar Maintenance

Proper chain maintenance ensures cutting efficiency and safety.

Chain Sharpening: Use round file matching chain pitch (4.0 mm). Maintain 30° cutting angle, 10° top plate angle.
Depth Gauges: File to 0.65 mm below cutter top plate. Use depth gauge tool.
Bar Maintenance: Clean groove, flip bar regularly for even wear. Dress rails with flat file if burred.
Chain Tension: Adjust so chain snaps back when pulled from bar. Tighten bar nuts after adjustment.
Lubrication: Use quality bar oil, adjust oiler for conditions. Check oil hole in bar for blockage.

CAUTION! Always wear cut-resistant gloves when handling chain.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No spark, fuel issues, flooded	Check spark, fuel freshness, carburetor. Use cold start procedure.
Engine starts then dies	Fuel filter clogged, vent blocked	Replace fuel filter, check tank vent.
Poor performance	Dirty air filter, exhaust blocked	Clean/replace air filter, clean spark arrestor.
Chain won't turn	Clutch worn, sprocket damaged	Inspect clutch springs and shoes, replace sprocket.
Excessive vibration	AV mounts worn, unbalanced parts	Replace anti-vibration mounts, check for bent crankshaft.
Chain oil not flowing	Oil hole blocked, pump defective	Clean oil passages, check oil pump worm gear.
Overheating	Dirty cooling fins, lean mixture	Clean fins, check carburetor adjustment.

Reset: For electronic issues, disconnect spark plug wire and pull starter 5 times to reset ignition module.

Parts List & Diagrams

Refer to Husqvarna Genuine Parts catalog for complete diagrams. Key part numbers:

Cylinder Kit: 503 87 47-01
Piston Kit: 537 23 40-01
Carburetor Kit: 545 01 40-01
Ignition Coil: 544 11 61-01
Clutch Assembly: 537 23 46-01
Chain Brake Band: 501 87 63-01
AV Mount Set: 537 23 42-01
Fuel Cap: 501 84 69-02

Note: Always use genuine Husqvarna parts for optimal performance and safety.

Warranty & Support

Husqvarna 42 comes with a 2-year commercial warranty and 1-year consumer warranty from date of purchase. Warranty covers defects in materials and workmanship under normal use. Not covered: wear items (chains, bars, spark plugs), damage from misuse, improper maintenance, or non-genuine parts.

For technical support, parts ordering, or dealer location:

Website: www.husqvarna.com
Customer Service: 1-800-487-5962
Technical Support: 1-800-848-9584
Find a Dealer: Use dealer locator on website

Macrovision: This manual is protected by copyright. No part may be reproduced without written permission from Husqvarna.