Husqvarna 240 Chainsaw Workshop Manual

The Husqvarna 240 is a lightweight, professional-grade chainsaw designed for demanding forestry and arborist work. This workshop manual provides comprehensive technical information for service, maintenance, and repair. It covers the 240 series, including specifications, engine details, fuel system, ignition, lubrication, chain brake, clutch, guide bar, chain, troubleshooting, and assembly/disassembly procedures. Below are key sections for safety, technical data, maintenance, repair, and troubleshooting.

1. Safety Precautions 2. Technical Specifications 3. Engine Overview 4. Fuel System 5. Ignition System 6. Lubrication System 7. Chain Brake & Clutch 8. Guide Bar & Chain 9. Maintenance Schedule 10. Disassembly & Assembly 11. Troubleshooting

Safety Precautions

Before performing any service, read all safety warnings. Use proper personal protective equipment (PPE).

Hazard	Precaution
Fuel & Fire	Work in well-ventilated area; no smoking; drain fuel before service.
Sharp Components	Wear cut-resistant gloves when handling chain, bar, or sharp edges.
Hot Surfaces	Allow engine and muffler to cool before touching.
Electrical	Disconnect spark plug wire to prevent accidental starting.
Chemical Exposure	Use gloves when handling fuel, oil, or cleaning solvents.
Lifting	Lift with legs, not back; use assistance for heavy components.
Tool Safety	Use correct tools; ensure torque specifications are followed.
Chain Tension	Adjust chain tension with engine off and cool.
Test Run	After repair, test in safe area clear of people and obstacles.
Disposal	Dispose of oil, fuel, and parts according to local regulations.

Technical Specifications

Key technical data for the Husqvarna 240 chainsaw.

Engine Type: 2-stroke, single cylinder, air-cooled.
Displacement: 38.2 cc (2.33 cu in).
Power Output: 1.8 kW (2.4 hp) at 9,000 rpm.
Fuel Tank Capacity: 0.33 L (0.87 US pt).
Oil Tank Capacity: 0.20 L (0.42 US pt).
Idle Speed: 2,700 rpm.
Maximum Power Speed: 9,000 rpm.
Ignition System: Electronic, capacitor discharge.
Spark Plug: Champion RCJ7Y or equivalent, gap 0.5 mm (0.020 in).
Carburetor: Zama C1Q-S137 or equivalent.
Guide Bar Length: 13" to 16" (33 cm to 40 cm).
Chain Pitch: 3/8" low profile.
Chain Gauge: 0.050" (1.3 mm).
Weight (without bar & chain): 4.4 kg (9.7 lbs).

Engine Overview

The engine is a 2-stroke design with piston-ported induction.

Cylinder & Piston: Aluminum cylinder with chrome-plated bore; forged aluminum piston.
Crankshaft: Supported by two ball bearings; includes integrated flywheel.
Crankcase: Split design; sealed with gasket.
Air Filter: Dual-stage foam and mesh; clean every 10 operating hours.
Muffler: Includes spark arrestor screen; clean periodically.
Cooling Fins: Keep cylinder temperature within operating range; must be kept clean.

WARNING! Do not run engine without air filter; can cause rapid piston/cylinder wear.

Fuel System

Fuel system includes tank, filter, lines, and carburetor.

Fuel Tank: Located at rear; includes vent and cap.
Fuel Filter: In-tank sintered bronze; replace annually or if clogged.
Fuel Lines: Two lines (supply and return); inspect for cracks/hardening.
Carburetor: Zama diaphragm type; adjustments: L (low speed), H (high speed), T (idle).
Fuel Mixture: Use 50:1 mix of unleaded gasoline (min 90 octane) and Husqvarna 2-stroke oil.

CAUTION! Never use straight gasoline or automotive oil; will cause engine seizure.

Ignition System

Electronic ignition with flywheel magneto and spark plug.

Ignition Module: Fixed timing; no adjustment.
Spark Plug: Champion RCJ7Y; gap 0.5 mm (0.020 in).
Stop Switch: Grounds ignition to stop engine.
Testing: Check for spark with plug removed and grounded to cylinder.

Tip: Weak or no spark indicates faulty module, broken wire, or stop switch failure.

Lubrication System

Automatic chain oiling with adjustable pump.

Oil Tank: Front-mounted; fill with Husqvarna chain oil or equivalent.
Oil Pump: Piston-type driven by worm gear on clutch drum.
Adjustment Screw: Located near clutch cover; turn clockwise to increase oil flow.
Oil Filter: In-tank mesh screen; clean during oil changes.
Oil Lines: From tank to pump and pump to bar pad; check for leaks.

WARNING! Never run chainsaw without bar oil; causes rapid bar and chain wear.

Chain Brake & Clutch

Inertia-activated chain brake and centrifugal clutch.

Chain Brake: Manual/automatic activation; band stops clutch drum. Test before each use.

Clutch: Drum and shoe type; engages at approximately 2,800 rpm. Inspect shoes for wear.

Clutch Drum: Includes worm gear for oil pump drive; check for scoring.

Spring: Holds brake band disengaged; replace if stretched or broken.

Guide Bar & Chain

Components for cutting; require regular maintenance.

Guide Bar: Roller nose or sprocket nose; flip regularly for even wear.
Bar Groove: Clean with bar groove cleaner; ensure oil holes are clear.
Chain: 3/8" low profile; sharpen with round file (4.0 mm) at 30° angle.
Depth Gauges: File down with flat file to maintain 0.65 mm (0.025 in) below cutter.
Tension Adjustment: Loosen bar nuts, adjust with screw, retighten nuts.

CAUTION! Dull or damaged chain increases kickback risk and reduces cutting efficiency.

Maintenance Schedule

Interval	Task
Daily	Check chain tension, sharpness; clean air filter; inspect for loose fasteners.
10 Hours	Clean spark arrestor screen; check clutch and brake function.
25 Hours	Replace fuel filter; clean cooling fins; inspect spark plug.
50 Hours	Clean carburetor (if needed); check fuel lines; inspect clutch shoes.
100 Hours	Decarbonize muffler; check crankshaft seals; replace spark plug.
Annual	Replace all filters; inspect piston/cylinder through exhaust port.

Note: Intervals vary with operating conditions; increase frequency in dusty environments.

Disassembly & Assembly

General procedure for major components.

Preparation: Drain fuel and oil; disconnect spark plug.
Cylinder Removal: Remove muffler, carburetor, then cylinder bolts; lift cylinder off.
Crankshaft Removal: Split crankcase after removing all screws; press out bearings.
Clutch Removal: Hold piston at TDC; use clutch tool to remove retaining nut.
Reassembly: Use new gaskets/seals; torque fasteners to specification.

Torque Values: Cylinder bolts: 10 Nm (7.4 ft-lb); Clutch nut: 35 Nm (26 ft-lb); Crankcase screws: 8 Nm (5.9 ft-lb).

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No spark, flooded, fuel issue	Check spark, plug condition; dry plug; clean carburetor, replace fuel.
Engine starts then dies	Clogged fuel filter, air leak	Replace fuel filter; check crankcase seals, intake manifold.
Loss of power	Clogged air filter, muffler, carb adjustment	Clean/replace air filter; decarbonize muffler; adjust carburetor.
Excessive vibration	Unbalanced flywheel, loose components	Check flywheel key; tighten bar nuts, engine mounts.
Chain doesn't stop with brake	Worn brake band, weak spring	Inspect brake band for wear; replace spring if weak.
Chain won't oil	Clogged oil passages, pump failure	Clean bar oil holes, tank filter; check pump drive gear.
Chain throws off bar	Loose chain, worn bar, damaged drive links	Adjust tension; inspect bar groove and rail; replace chain if damaged.
Clutch slips	Worn shoes, oily drum	Replace clutch shoes; clean drum with solvent.

Service Note: For complex repairs, refer to detailed diagrams or contact authorized Husqvarna service center.

Support: Husqvarna Customer Service: 1-800-487-5952; www.husqvarna.com