Husqvarna 445 Chainsaw Parts Manual

The Husqvarna 445 is a professional-grade chainsaw designed for demanding tasks, featuring a powerful X-Torq® engine for reduced emissions and fuel consumption, an efficient air injection system, and a robust construction for durability. This manual provides detailed parts identification, diagrams, ordering information, and maintenance guidance to ensure optimal performance and safety. Below are key sections covering parts overview, assembly diagrams, specifications, maintenance, and troubleshooting.

1. Parts Overview & Identification 2. Assembly Diagrams 3. Specifications 4. Maintenance & Replacement Parts 5. Safety Components 6. Engine & Power System Parts 7. Cutting Equipment Parts 8. Ordering Information 9. Care & Storage 10. Regulatory Information 11. Troubleshooting

Parts Overview & Identification

Key components: Engine assembly (cylinder, piston, carburetor), Cutting equipment (guide bar, chain, sprocket), Safety features (chain brake, throttle lock, front handguard), and Control systems (ignition, fuel system).

Part Category	Description
Engine Assembly	Includes cylinder, piston, crankshaft, carburetor, and ignition module
Cutting Equipment	Guide bar, saw chain, drive sprocket, chain tensioner
Safety Components	Chain brake, throttle lockout, front handguard, right hand guard
Fuel System	Fuel tank, fuel filter, fuel lines, carburetor assembly
Air Filtration	Air filter, filter cover, pre-cleaner
Control Systems	Throttle trigger, stop switch, choke control, decompression valve
Exhaust System	Muffler, spark arrestor screen, exhaust cover
Handle & Body	Front handle, rear handle, anti-vibration system, body casing
Starter Assembly	Starter pulley, recoil spring, starter handle, rope
Bar & Chain Lubrication	Oil pump, oil tank, oil lines, adjustment screw

Assembly Diagrams

Refer to exploded-view diagrams for part location and assembly sequence.

Engine Assembly: Diagram showing cylinder, piston, connecting rod, crankshaft bearings.
Cutting Attachment: Diagram of guide bar mounting, chain tensioner, sprocket cover.
Fuel System: Layout of fuel tank, filter, lines, and carburetor connections.
Air Filter System: Assembly of filter cover, pre-cleaner, and filter element.
Starter Assembly: Exploded view of recoil starter components.

WARNING! Always disconnect spark plug before disassembly. Use proper tools and follow torque specifications.

Specifications

Engine Model: Husqvarna 445 X-Torq®.
Displacement: 45.7 cc (2.8 cu. in.).
Power Output: 2.4 kW (3.2 hp).
Fuel Capacity: 0.5 L (16.9 fl. oz).
Oil Capacity (Bar & Chain): 0.25 L (8.5 fl. oz).
Recommended Bar Lengths: 13" to 18" (33 cm to 45 cm).
Chain Pitch: 3/8" or .325".
Weight (Powerhead): 4.9 kg (10.8 lbs) without cutting equipment.
Ignition System: Electronic, semi-transistorized.
Sound Pressure Level: 106 dB(A).

Maintenance & Replacement Parts

Regular maintenance ensures longevity. Replace parts as per service intervals.

Common Replacement Parts: Air filter (Part # 503 92 96-01), Spark plug (BRISK QR 603S or equivalent), Fuel filter, Saw chain (varies by bar length), Guide bar (varies by length/pitch), Drive sprocket (rim or spur type), Chain brake band, Anti-vibration buffers.

Maintenance Schedule: Daily - Check chain tension, lubrication. Weekly - Clean air filter, check for loose parts. Monthly - Inspect spark plug, fuel filter, bar wear. Annually - Professional servicing recommended.

Safety Components

Critical safety parts must be functional and undamaged.

Chain Brake: Includes brake band, handle, and activation mechanism. Test before each use.
Throttle Lockout: Prevents accidental throttle engagement. Ensure it springs back.
Front Handguard: Protects right hand from kickback and debris.
Right Hand Guard: Additional protection near throttle.
Stop Switch: Must immediately stop engine when engaged.

CAUTION! Never operate chainsaw with damaged or missing safety parts.

Engine & Power System Parts

Engine parts require precise fitting and proper lubrication.

Cylinder & Piston Kit: Includes cylinder, piston, piston rings, wrist pin, and circlips.
Carburetor Kit: Diaphragms, gaskets, needles, and adjustment screws.
Ignition Module: Controls spark timing; replace if engine misfires or won't start.
Fuel Pump Diaphragm: Part of carburetor assembly; replace if fuel delivery is poor.
Decompression Valve: Eases starting; ensure it seals properly when closed.

Tip: Use genuine Husqvarna parts for engine repairs to maintain performance and emissions compliance.

Cutting Equipment Parts

Proper cutting equipment ensures efficient and safe operation.

Guide Bar: Choose correct length, pitch, and gauge. Inspect for wear, straightness, and rail damage.
Saw Chain: Match pitch and gauge to bar and sprocket. Keep sharp and properly tensioned.
Drive Sprocket: Rim type (easier replacement) or spur type. Replace when worn (hooks on drive links).
Chain Tensioner: Includes screw, pinion, and adjustment mechanism. Keep clean and functioning smoothly.
Sprocket Cover (Clutch Cover): Protects clutch and sprocket; includes chain brake components.

WARNING! Always stop engine and wear protective gloves when handling cutting equipment.

Ordering Information

Use Husqvarna part numbers for accurate ordering. Contact authorized dealer or visit Husqvarna website.

Example Part Numbers: Air Filter (503 92 96-01), Spark Plug (BRISK QR 603S or Husqvarna 503 87 45-01), Complete Cylinder Kit (537 00 74-03), Chain Brake Band (537 01 12-01), 16" Guide Bar (531 00 04-16), .325" Pitch Chain (531 30 04-48).

Provide model number (445) and serial number when ordering. Check for superseded part numbers.

Care & Storage

Clean chainsaw after each use. Drain fuel for long-term storage. Store in dry, cool place.

CAUTION! Never use pressure washer; water can enter engine and bearings. Use recommended cleaning agents.

Regulatory Information

EPA and CARB compliant. Meets ANSI B175.1 safety standards. Contains parts protected by patents and trademarks. Copyright © Husqvarna AB. For support, visit www.husqvarna.com or contact authorized service dealer. Always follow local regulations for operation and disposal.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Fuel issues, spark, compression	Check fuel freshness, spark plug, decomp valve, carburetor settings.
Engine runs poorly/dies	Clogged filter, carb adjustment	Clean/replace air/fuel filter; adjust carburetor (H/L screws).
Chain doesn't turn	Clutch, sprocket, brake engaged	Check clutch springs/shoes, sprocket wear, disengage chain brake.
Excessive vibration	Loose parts, AV buffers, imbalance	Tighten all fasteners; replace anti-vibration buffers; balance cutting equipment.
Chain throws/comes off	Improper tension, worn bar, damaged drive links	Correct tension; inspect bar rails and sprocket; replace chain if damaged.
Poor oiling	Clogged oil passages, pump, tank vent	Clean oil ports, filter; check pump operation; ensure tank vent is clear.

Service: For complex repairs, contact authorized Husqvarna service dealer. Use genuine parts.

Support: 1-800-HUSKY62; www.husqvarna.com