Husqvarna Chainsaw Repair Manual 350

The Husqvarna Chainsaw Model 350 is a professional-grade chainsaw designed for demanding cutting tasks. This repair manual provides detailed instructions for maintenance, troubleshooting, and repair of the engine, fuel system, ignition, chain brake, bar, chain, and other critical components. It is intended for qualified technicians and experienced users. Below are key sections covering safety, specifications, maintenance procedures, disassembly, assembly, and troubleshooting.

Safety Precautions

Before performing any repair or maintenance, read and understand all safety warnings. Always wear appropriate personal protective equipment (PPE).

WARNING! Failure to follow safety instructions can result in serious injury or death. Use genuine Husqvarna parts.

Specifications & Identification

Identify your saw using the serial number plate located on the rear housing.

• Model: Husqvarna 350
• Engine Type: 2-stroke, single cylinder, air-cooled
• Displacement: 50.1 cc (3.06 cu in)
• Power Output: 3.2 hp (2.4 kW)
• Fuel Tank Capacity: 0.95 L (0.25 US gal)
• Oil Tank Capacity: 0.26 L (0.07 US gal)
• Ignition System: Electronic, SEM or similar
• Carburetor: Walbro HDA or Zama C1M
• Recommended Bar Length: 13" to 20" (33 cm to 50 cm)
• Spark Plug: Champion RCJ7Y or equivalent, gap 0.5 mm (0.020")

Routine Maintenance

Regular maintenance ensures optimal performance and longevity.

1. Daily/Before Use: Check chain tension, sharpness, and lubrication. Inspect for loose nuts/bolts.
2. Air Filter: Clean weekly (more often in dusty conditions). Remove, tap clean, or wash in warm soapy water if foam. Dry completely before reinstallation.
3. Spark Plug: Check every 25 operating hours. Clean electrodes, adjust gap, or replace if worn.
4. Fuel Filter: Replace every 50 hours or annually. Use Husqvarna part # 501 87 94-01.
5. Chain Sprocket: Inspect for wear every 100 hours. Replace if teeth are hooked or worn.
6. Cylinder Fins: Keep cooling fins clean to prevent overheating.

CAUTION! Use only Husqvarna XP® or equivalent high-quality 2-stroke oil at a 50:1 mix ratio with fresh unleaded gasoline (min 90 octane).

Fuel System

Components: Fuel tank, cap, lines, filter, carburetor, and purge bulb.

1. Fuel Line Replacement: Drain tank. Remove old lines from tank grommets and carburetor. Cut new lines to length, insert, and ensure secure connections.
2. Carburetor Removal: Disconnect fuel lines and throttle linkage. Remove mounting nuts. Carefully lift carburetor away from intake manifold.
3. Diaphragm & Gasket Inspection: Disassemble carburetor. Check pump and metering diaphragms for cracks or stiffness. Replace kit if necessary.
4. Fuel Filter: Pull from tank using a wire hook. Replace with new filter.

Tip: Always pressure test the fuel system after reassembly to check for leaks.

Ignition System

Components: Flywheel, ignition coil (module), spark plug, and stop switch.

1. Spark Test: Remove spark plug, reconnect boot, ground plug against cylinder. Pull starter rope – look for strong blue spark.
2. Coil Air Gap: Set gap between coil legs and flywheel magnets to 0.3 mm (0.012") using a feeler gauge.
3. Flywheel Removal: Use a flywheel puller (Husqvarna tool # 502 50 41-01). Do not strike with hammer.
4. Stop Switch Test: Disconnect wire from coil. If spark returns, switch is faulty.

WARNING! A weak or no spark is often due to a dirty flywheel magnet, incorrect gap, or faulty coil.

Cylinder & Piston

Inspect for scoring, carbon buildup, and ring wear.

1. Remove Muffler: Inspect piston through exhaust port. Look for vertical scoring.
2. Cylinder Removal: Remove engine covers, carburetor, and intake. Unbolt cylinder base nuts. Lift cylinder carefully.
3. Piston Removal: Remove circlips from piston pin. Heat piston if necessary and push pin out.
4. Decarbonizing: Remove carbon from piston crown and exhaust port with a soft tool. Do not scratch surfaces.
5. Inspection: Measure cylinder bore and piston skirt for wear/out-of-round. Replace if beyond service limits.

CAUTION! Always replace piston rings when reassembling. Lubricate with 2-stroke oil during assembly.

Chain Brake & Clutch

The chain brake stops the chain in milliseconds if activated by kickback or manually.

1. Band Inspection: Check brake band for wear or cracks. Replace if thickness is less than 0.8 mm.
2. Spring Replacement: The brake spring is high-tension. Use proper handling tools. Wind spring clockwise into housing.
3. Clutch Removal: Hold piston with rope in spark plug hole. Remove clutch nut (left-hand thread). Use clutch tool # 502 77 94-02.
4. Clutch Drum & Sprocket: Inspect for grooves from chain contact. Replace if deep scoring is present.

WARNING! Never operate a chainsaw with a defective or removed chain brake.

Guide Bar & Saw Chain

Proper care extends bar and chain life.

1. Bar Maintenance: Clean bar groove weekly. Flip bar weekly for even wear. File down burrs on rails.
2. Chain Sharpening: Use correct round file size (typically 4.0 mm or 5/32"). Maintain correct filing angle (usually 30°). Keep all cutters equal length.
3. Depth Gauge Setting: File down depth gauges (rakers) after several sharpenings. Use a depth gauge tool for correct height (approx. 0.65 mm below cutter).
4. Tension Adjustment: Chain should be snug against bar but pull freely by hand. Re-tighten after first few cuts on a new chain.

Tip: Always run the chain at full throttle when cutting. A dull chain causes excessive wear and is dangerous.

Carburetor Adjustment

Factory settings (screw turns out from lightly seated):

• L (Low Speed): 1 turn
• H (High Speed): 1 turn
• T (Idle): 1 turn

1. Preliminary Setting: Set L and H to 1 turn out. Start engine, warm up for 5 minutes.
2. Idle Speed (T): Adjust so chain just stops moving. Engine must run steadily.
3. Low Speed (L): Turn L screw for fastest, smoothest idle. Then enrich slightly (1/8 turn) for good acceleration.
4. High Speed (H): CAUTION: Use tachometer. Max RPM under load should be 13,000 - 13,500 RPM. Do not over-lean.
5. Final Idle Check: Re-check idle speed after H and L adjustments.

WARNING! An overly lean H setting will cause engine seizure. If in doubt, set richer.

Troubleshooting Guide

Torque Specifications

Use a calibrated torque wrench for critical fasteners.

Service Support: For technical assistance or genuine parts, contact your authorized Husqvarna dealer or visit www.husqvarna.com.