Husqvarna 240 Chainsaw Service Manual

The Husqvarna 240 is a lightweight, professional-grade chainsaw designed for demanding users. This service manual provides detailed instructions for maintenance, troubleshooting, and repair of the chainsaw's engine, cutting equipment, and safety systems. Key sections include safety precautions, specifications, maintenance schedules, fuel system service, ignition system, carburetor adjustment, chain brake inspection, and detailed troubleshooting procedures.

1. Features at a Glance 2. Safety Precautions 3. Specifications 4. Maintenance Schedule 5. Fuel System Service 6. Ignition System 7. Carburetor Adjustment 8. Chain & Bar Maintenance 9. Chain Brake Inspection 10. Troubleshooting 11. Parts Diagram & Ordering

Features at a Glance

Key components: X-Torq® engine for reduced emissions, Air Injection™ air cleaning system, LowVib® anti-vibration system, Smart Start® for easy starting, 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 cm³ (2.5 cu.in.)
Power Output	1.8 kW (2.4 hp)
Fuel Tank Volume	0.33 liter (0.71 US pint)
Oil Tank Volume	0.25 liter (0.53 US pint)
Recommended Bar Length	13" - 16" (33 cm - 40 cm)
Chain Pitch	3/8" Low Profile or .325"
Weight (excl. cutting equipment)	4.4 kg (9.7 lbs)
Sound Pressure Level (LpA)	104 dB(A)
Vibration Level (Front/Rear Handle)	3.2/2.8 m/s²

Safety Precautions

Always wear appropriate Personal Protective Equipment (PPE): helmet with visor and hearing protection, protective gloves, chainsaw protective trousers, and safety boots.

Work Area Safety: Keep bystanders and animals away. Ensure secure footing.
Fuel Safety: Refuel outdoors with engine stopped. Wipe off spills. Move at least 3m from refueling point before starting.
Kickback Zone: Be aware of the upper quadrant of the bar tip. Do not cut with this area.
Chain Brake: Test function before each use. Ensure it engages properly.
Maintenance Safety: Disconnect spark plug cap before performing any maintenance.

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

Specifications

Engine Model: Husqvarna 240.
Cylinder Bore: 38 mm (1.5 in).
Piston Stroke: 36 mm (1.42 in).
Ignition System: SEM electronic, fixed timing.
Spark Plug: Champion RCJ7Y or equivalent, gap 0.5 mm (0.020").
Carburetor: Zama C1Q-S267 or Walbro WT-645.
Idle Speed: 2700 rpm.
Maximum Power Speed: 9000 rpm.
Fuel/Oil Mix Ratio: 50:1 (Husqvarna XP+ or equivalent high-quality 2-stroke oil).
Chain Oil: Biodegradable chain oil recommended.

Maintenance Schedule

Access OSD via TV MENU or SETUP (DVD). Front Panel: POWER, OPEN/CLOSE, AUTO/DPMS, MUTE.

Daily/Before Use: Check chain tension, sharpness, and lubrication. Check chain brake function. Clean air filter. Check for loose nuts/bolts.

Weekly/Every 10 Hours: Clean cooling fins and cylinder cover. Clean spark arrestor screen in muffler (if equipped). Check spark plug condition and gap.

Monthly/Every 20 Hours: Clean fuel filter. Check fuel line for cracks. Clean carburetor air intake.

Annually/Every 100 Hours: Replace fuel filter. Check and clean carburetor diaphragm. Check clutch drum and sprocket for wear. Check anti-vibration elements.

Fuel System Service

Fuel Tank: Drain old fuel. Clean tank with clean gasoline. Inspect for cracks.

Fuel Filter: Remove through filler neck with hook tool. Replace if dirty or clogged.
Fuel Line: Inspect for brittleness or cracks. Replace in sections: tank to carburetor, carburetor to primer bulb (if equipped).
Carburetor Removal: Disconnect fuel line, throttle linkage, and choke rod. Remove mounting nuts.
Diaphragm Check: Remove carburetor cover. Inspect pump and metering diaphragms for stiffness or holes. Replace kit if necessary.

Tip: Always use fresh, properly mixed fuel. Stale fuel is a common cause of starting and running problems.

Ignition System

Spark Plug: Remove, clean electrodes with wire brush. Check gap (0.5 mm / 0.020"). Replace if electrodes are worn or insulator is cracked.

Ignition Coil (Module): Check air gap between coil legs and flywheel magnets (0.2-0.4 mm / 0.008-0.016"). Adjust by loosening mounting screws.
Stop Switch: Test for continuity between black wire and ground when switch is OFF (should be 0 ohms). When ON, should be open circuit (infinite resistance).
Wiring Harness: Inspect for frayed or broken wires, especially near handles and where it passes through chassis.
Flywheel Key: If engine backfired or timing is off, remove flywheel and check Woodruff key for shearing. Replace if damaged.

WARNING! Disconnect spark plug cap before testing ignition system to prevent accidental starting.

Carburetor Adjustment

Factory settings (Zama C1Q-S267): L (Low) = 1 turn out, H (High) = 1 turn out, T (Idle) = 1 turn out. Final adjustment requires tachometer and warmed-up engine.

Initial Setting: Turn H and L needles gently clockwise to seat, then back out to factory setting.
Start Engine: Warm up for several minutes.
Idle Speed (T): Adjust so chain does not move and engine runs smoothly (~2700 rpm).
High Speed (H): With throttle fully open, adjust for maximum RPM, then turn counter-clockwise (richer) until RPM drops slightly (approx. 12,800-13,200 rpm max).
Low Speed (L): From idle, accelerate quickly. If it hesitates, turn L counter-clockwise (richer) in 1/8 turn increments until acceleration is crisp.
Re-check Idle: Readjust T if necessary after L/H changes.

CAUTION! Running engine too lean (needles turned in too far) can cause severe engine damage from overheating.

Chain & Bar Maintenance

Chain Sharpening: Use correct round file size (typically 4.0 mm / 5/32" for 3/8" LP). Maintain 30° top plate cutting angle and 10° file tilt. Keep all cutters equal length.

Bar Care: Clean bar groove weekly. Flip bar weekly for even wear. Dress bar rails with flat file if burred. Check for even wear and "curling" of rails.

Chain Brake Inspection

Manual Engagement: Pull front hand guard towards front handle. It should engage with a distinct click and lock.

Inertia Test: With saw on ground, grip rear handle and sharply rotate front handle forward. Brake should engage.
Band Inspection: Remove clutch cover and bar. Inspect brake band for cracks, wear, or glazing. Minimum thickness: 0.7 mm (0.028").
Spring Check: Check tension of return spring. It should retract hand guard fully when released.
Mechanism: Clean and lubricate pivot points with light oil. Ensure no sawdust buildup.

CAUTION! Never operate a chainsaw with a faulty or inoperative chain brake.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine will not start	No spark, flooded, stale fuel, clogged filter	Check spark, dry plug, use fresh fuel mix, clean/replace filter.
Engine starts then dies	Clogged fuel tank vent, dirty carburetor, faulty diaphragm	Clean vent, service carburetor, replace diaphragm kit.
Lacks power under load	Dirty air filter, clogged spark arrestor, lean H setting	Clean filter & arrestor, adjust H richer, check compression.
Chain does not oil	Empty oil tank, clogged oil passages, worn pump	Fill tank, clean bar groove & outlet hole, inspect/replace pump.
Excessive vibration	Loose components, unbalanced chain, worn AV mounts	Tighten bolts, sharpen chain evenly, replace AV buffers.
Chain rotates at idle	Idle speed too high, clutch springs worn	Adjust T screw lower, inspect/replace clutch drum/springs.

Compression Test: Should be minimum 110 psi (7.6 bar). Low compression indicates worn piston/rings or scored cylinder.

Parts Diagram & Ordering

Refer to the official Husqvarna 240 IPL (Illustrated Parts List) for part numbers and exploded views of assemblies: Engine, Fuel System, Ignition, Clutch & Chain Brake, Cutting Equipment.

For genuine Husqvarna parts and service support, contact an authorized Husqvarna dealer or visit www.husqvarna.com. Always use genuine parts to ensure safety and performance.

Service Support: 1-800-487-5962; www.husqvarna.com/us/support