Husqvarna 350 Chainsaw Service Manual
The Husqvarna 350 is a professional-grade chainsaw featuring a 50.1cc X-Torq engine for reduced emissions and fuel consumption, an air injection system for cleaner air filters, combined choke/stop control, inertia-activated chain brake, low vibration system, and automatic chain oiler. This service manual provides detailed instructions for maintenance, troubleshooting, repair, and safety procedures to ensure optimal performance and longevity of your chainsaw.
Safety Precautions
Always prioritize safety when operating, maintaining, or servicing the Husqvarna 350 chainsaw. Failure to follow safety guidelines can result in serious injury or death.
| Area | Precaution |
|---|
| Personal Protective Equipment (PPE) | Always wear safety glasses, hearing protection, gloves, chainsaw chaps/pants, and sturdy boots. |
| Work Area | Ensure a clear, stable work area free of tripping hazards. Keep bystanders at a safe distance. |
| Before Starting | Check chain tension, chain brake function, and ensure all guards are in place. Verify no fuel leaks. |
| During Operation | Hold the saw firmly with both hands. Do not operate above shoulder height. Beware of kickback. |
| During Maintenance | Allow the engine to cool completely. Disconnect the spark plug wire before performing any service. |
| Fuel Handling | Refuel outdoors, away from ignition sources. Use fresh, clean fuel mix (50:1 Husqvarna XP+ oil). |
Specifications & Technical Data
- Engine Model: Husqvarna 350
- Engine Displacement: 50.1 cc (3.06 cu. in.)
- Engine Power: 3.1 HP (2.3 kW)
- Fuel Tank Volume: 0.95 US pints (0.45 liters)
- Oil Tank Volume: 0.63 US pints (0.30 liters)
- Recommended Bar Length: 13" to 20" (33 cm to 50 cm)
- Chain Pitch: 3/8" or .325" (depending on configuration)
- Chain Gauge: 0.050" or 0.058"
- Idle Speed: 2,700 RPM
- Maximum Power Speed: 9,600 RPM
- Ignition System: Electronic, air gap 0.30 mm (0.012 in.)
- Spark Plug: Champion RCJ7Y or equivalent, gap 0.5 mm (0.020 in.)
- Weight (powerhead only): 11.7 lbs (5.3 kg)
Component Identification
Key components of the Husqvarna 350 chainsaw for reference during service.
- Front Handle/Hand Guard: Houses the chain brake trigger and throttle lockout.
- Rear Handle: Contains the throttle trigger, master control lever (choke/stop), and start/stop switch.
- Fuel Cap: Secures the fuel tank; includes a vent.
- Oil Cap: Secures the chain oil tank.
- Air Filter Cover: Protects the air filter; secured by snap locks or screws.
- Muffler: Reduces exhaust noise and directs gases away.
- Chain Catcher: Safety device designed to catch a broken or derailed chain.
- Chain Brake Handle: Manually activates the chain brake if pushed forward.
- Bar & Chain: The cutting assembly.
- Clutch Cover/Sprocket Cover: Protects the clutch and drive sprocket.
WARNING! Familiarize yourself with all controls and components before operation or service.
Routine Maintenance
Regular maintenance is crucial for safety, performance, and saw life. Follow this schedule.
| Interval | Task | Procedure |
|---|
| Before each use | Check chain tension | Adjust so chain snaps back against bar but can be pulled by hand. |
| Before each use | Check chain sharpness & condition | Sharpen or replace as needed. Check for damaged or worn drive links. |
| Before each use | Inspect chain brake function | Activate manually; ensure it engages and stops the chain. |
| Daily | Clean air filter | Remove, tap clean, or wash in warm soapy water. Dry completely before reinstalling. |
| Daily | Check bar condition | Clean bar groove, flip bar regularly for even wear. Check for wear on rails and sprocket nose. |
| Weekly | Clean cooling fins & cylinder area | Remove debris from fins, muffler area, and under clutch cover. |
| As needed | Clean spark arrestor screen (if equipped) | Remove from muffler and clean with wire brush. |
Engine Service
Procedures for maintaining and servicing the engine components.
- Cylinder & Piston Inspection: Remove muffler to inspect piston skirt and rings for scoring. Light scoring can be cleaned with fine emery cloth. Heavy scoring requires cylinder/piston replacement.
- Compression Check: Use a compression gauge. Healthy compression should be above 120 PSI. Low compression indicates worn rings, piston, or cylinder.
- Carburetor Adjustment (HLS-298C): Factory settings: L=1 turn out, H=1 turn out, T=1 turn out. Fine-tune at operating temperature. Adjust L for smooth idle, H for max RPM (not exceeding 9,600 RPM).
- Replacing Fuel Lines & Filter: Drain fuel tank. Remove old lines and filter from inside tank. Install new filter and lines, ensuring a tight fit on tank grommets and carburetor fittings.
CAUTION! Engine components are precision parts. Handle with care and use proper tools.
Fuel System
Maintenance of the fuel tank, lines, filter, and carburetor.
- Fuel Mix: Use 89 octane or higher unleaded gasoline mixed with a high-quality 2-stroke oil at a 50:1 ratio (Husqvarna XP+ recommended).
- Fuel Filter Replacement: Replace annually or if clogged. Use a wire or hook to extract the filter from the tank.
- Carburetor Diaphragms: If saw runs poorly or leaks fuel, the carburetor may need a rebuild kit (diaphragms, gaskets, needle valve).
- Fuel Tank Vent: Located in the fuel cap. If tank develops a vacuum, clean the vent hole with a fine wire.
WARNING! Never use fuel mix older than 30 days. Stale fuel is a primary cause of starting and running problems.
Ignition System
Service procedures for the spark plug, ignition coil, and wiring.
- Spark Plug Service: Remove, clean electrodes with wire brush. Check gap (0.5 mm / 0.020 in.) and adjust if necessary. Replace if electrodes are heavily eroded or insulator is cracked.
- Ignition Coil Air Gap: The gap between the coil legs and the flywheel magnets should be 0.30 mm (0.012 in.). Use a feeler gauge to set. Incorrect gap can cause weak or no spark.
- Stop Switch Test: With spark plug removed and connected to the coil, ground the plug's base against the cylinder. Pull the starter. Spark should be bright blue. Activate the stop switch; spark should cease. If not, check switch wiring and connections.
Chain & Bar Maintenance
Proper care of the cutting attachment ensures safety and cutting efficiency.
- Chain Sharpening: Use a round file matching the chain's cutter size (typically 5/32" for .325" chain, 7/32" for 3/8" chain). Maintain the specified filing angle (usually 30°). File all cutters to the same length.
- Bar Maintenance: Clean the bar groove with a narrow screwdriver or bar groove cleaner. File down any burrs on the bar rails. Lubricate the sprocket nose hole regularly.
- Drive Sprocket: Inspect for wear. A worn sprocket (hooked teeth) will accelerate chain wear. Replace with a matching type (rim or spur).
- Chain Oil Flow Check: Run the saw at high RPM with the bar tip pointed at a light-colored surface (like a stump) about 6 inches away. A fine line of oil should be visible. Adjust oiler screw if flow is inadequate.
Clutch & Drive System
Service instructions for the clutch, drum, and bearing.
- Clutch Removal: Remove the clutch cover, bar, and chain. Use a piston stop to lock the crankshaft. Use a clutch removal tool to unscrew the clutch (left-hand threads - turn clockwise to loosen).
- Clutch Inspection: Check clutch shoes for wear and spring tension. Worn or weak springs will cause poor engagement. Replace clutch assembly if shoes are heavily worn.
- Clutch Drum & Bearing: Inspect the drum for scoring where the chain runs. Check the needle bearing inside the drum for smooth rotation. Replace if rough or noisy.
- Reassembly: Apply a small amount of grease to the needle bearing. Torque the clutch to specification (see Section 11).
Troubleshooting Guide
| Symptom | Possible Cause | Corrective Action |
|---|
| Engine will not start | No spark, stale fuel, flooded engine, clogged air filter, faulty carburetor. | Check spark, use fresh fuel, clear flood, clean air filter, rebuild carburetor. |
| Engine starts but dies | Clogged fuel filter, faulty fuel line, dirty carburetor, faulty ignition coil. | Replace fuel filter & lines, clean carburetor, check coil air gap and spark. |
| Engine lacks power | Clogged air filter, dirty spark arrestor, carburetor out of adjustment, low compression. | Clean filter and spark arrestor, adjust carburetor, perform compression test. |
| Chain does not stop with brake engaged | Worn brake band, dirty/ oily mechanism, faulty spring. | Clean brake components, inspect band for wear, replace brake assembly if necessary. |
| Excessive chain vibration or noise | Loose chain, damaged bar, worn drive sprocket, worn clutch. | Tension chain properly, inspect and replace bar/sprocket/clutch as needed. |
| Chain does not oil | Empty oil tank, clogged oil passages, faulty oil pump, worn pump drive. | Fill tank, clean bar oil hole and tank outlet, inspect/replace oil pump. |
Torque Specifications
Use a torque wrench for critical fasteners to prevent damage.
| Component | Thread Size | Torque (Nm) | Torque (ft-lbs) |
|---|
| Cylinder Base Nuts | M6 | 10-12 Nm | 7.4-8.9 ft-lbs |
| Muffler Bolts | M6 | 8-10 Nm | 5.9-7.4 ft-lbs |
| Clutch | M14x1.0 LH | 35-40 Nm | 25.8-29.5 ft-lbs |
| Flywheel Nut | M12x1.25 | 40-45 Nm | 29.5-33.2 ft-lbs |
| Spark Plug | M14x1.25 | 20-25 Nm | 14.8-18.4 ft-lbs |
| Bar Mounting Nuts | M8 | 12-15 Nm | 8.9-11.1 ft-lbs |
Service Support: For genuine Husqvarna parts and technical assistance, contact your authorized Husqvarna dealer or visit www.husqvarna.com.
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