450 Husqvarna Chainsaw Manual

The Husqvarna 450 is a professional-grade gasoline chainsaw designed for demanding cutting tasks. It features a powerful X-Torq engine for reduced emissions and fuel consumption, an inertia-activated chain brake for safety, combined choke/stop control for easy starting, air injection for extended air filter life, and a low vibration system for operator comfort. Below are key sections for safety, features, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: X-Torq engine, inertia-activated chain brake, combined choke/stop control, air injection system, low vibration handles, side-mounted chain tensioner, and quick-release air filter.

Safety Information

Read all instructions before operation. Always wear proper protective equipment.

1. Personal Protective Equipment: Wear safety glasses, hearing protection, gloves, chainsaw chaps, and steel-toed boots.
2. Work Area Safety: Keep bystanders and pets at least 15 feet away. Ensure secure footing.
3. Chain Brake: Test before each use by pulling forward on front hand guard.
4. Fuel Safety: Refuel in well-ventilated area with engine off and cool. Use fresh fuel mix.

WARNING! Kickback can occur without warning. Always hold saw firmly with both hands. Never operate above shoulder height.

Assembly & First Use

Unpack and inspect contents. Assemble guide bar and chain.

1. Install guide bar and chain: Place bar on mounting studs, loop chain around sprocket and bar groove, adjust tension.
2. Add fuel mixture: Use 50:1 mix of unleaded gasoline and Husqvarna 2-stroke oil. Fill fuel tank.
3. Add chain oil: Fill separate oil tank with quality bar and chain oil.
4. Start engine: Place on flat surface, engage chain brake, set master control to choke, pull starter cord.

CAUTION! Ensure chain brake is engaged when starting. Keep hands away from chain at all times.

Specifications

• Engine Displacement: 50.2 cc
• Power Output: 3.2 HP
• Fuel Tank Volume: 14.9 oz (0.44 liters)
• Oil Tank Volume: 8.5 oz (0.25 liters)
• Recommended Bar Length: 16" to 20"
• Chain Pitch: 3/8"
• Chain Gauge: 0.050"
• Weight (without bar/chain): 10.8 lbs (4.9 kg)
• Sound Pressure Level: 106 dB(A)
• Vibration Levels: Front handle 3.2 m/s², Rear handle 4.5 m/s²

Controls and Components

Main controls located on top and rear of saw body. Front Handle: Contains throttle trigger and throttle lockout. Rear Handle: Contains master control lever (choke/run/stop).

Key Components: Chain brake handle, front hand guard, chain catcher, spark plug cover, muffler, fuel cap, oil cap, decompression valve (if equipped), starter handle.

Operation Controls: Master control lever (choke position for cold start, run position for operation, stop position to shut off). Throttle trigger with lockout (prevents accidental acceleration). Chain brake lever (manual activation). Decompression valve (reduces starting effort).

Operation Guide

Starting Procedure: Engage chain brake. Set master control to choke. Press decompression valve (if equipped). Pull starter cord until engine fires. Set master control to run. Pull starter cord to start. Disengage chain brake before cutting.

1. Basic Cutting: Hold saw firmly. Let chain reach full speed before contacting wood. Use bottom of bar for cutting.
2. Felling Trees: Plan escape path. Make notch cut first, then felling cut. Use wedges for large trees.
3. Limbing: Work from trunk outward. Keep saw stable, avoid contacting ground.
4. Bucking: Support logs properly. Cut from top down for supported logs, from bottom up for suspended logs.

Tip: Never cut with just the tip of the bar. Maintain proper chain tension to prevent derailment.

Maintenance Schedule

Daily/Before Each Use: Check chain tension, sharpness, and lubrication. Check fuel and oil levels. Inspect for loose fasteners. Clean air filter if dirty.

Weekly/Every 10 Hours: Clean cooling fins. Check spark plug condition. Clean fuel filter. Inspect guide bar for wear.

Monthly/Every 50 Hours: Replace spark plug. Clean carburetor air filter. Check anti-vibration elements. Clean exhaust port and spark arrestor screen.

Annually/Every 100 Hours: Replace fuel filter. Check all safety devices. Have professional service if needed.

WARNING! Always disconnect spark plug wire before performing maintenance. Use only Husqvarna replacement parts.

Chain Sharpening & Tensioning

Proper chain maintenance ensures optimal performance and safety.

1. Chain Tensioning: Loosen bar nuts. Adjust tensioning screw until chain fits snug against bar. Tighten bar nuts while lifting bar tip.
2. Sharpening: Use round file matching chain pitch (typically 5/32"). Maintain 30° cutting angle. File all cutters to equal length.
3. Depth Gauge Setting: Use depth gauge tool to maintain proper height (0.025" typically). File depth gauges after several sharpenings.
4. Inspection: Check for damaged or broken cutters. Replace chain if excessively worn or damaged.

CAUTION! Wear gloves when handling chain. Ensure chain is properly tensioned before operation.

Storage Guidelines

Long-term storage requires proper preparation to prevent damage.

1. Empty fuel tank or add fuel stabilizer and run for 2 minutes.
2. Run carburetor dry by disconnecting fuel line and running until engine stops.
3. Remove chain, clean and soak in oil. Clean guide bar groove and oil hole.
4. Clean entire saw, especially cooling fins and air filter.
5. Store in dry, dust-free location with bar and chain separately.

CAUTION! Never store with fuel in tank for more than 30 days without stabilizer. Store out of reach of children.

Warranty Information

Husqvarna 450 chainsaw includes limited warranty covering defects in materials and workmanship. Residential warranty: 2 years. Commercial warranty: 1 year. Warranty does not cover normal wear, misuse, improper maintenance, or use of non-genuine parts. Proof of purchase required. For warranty service, contact authorized Husqvarna dealer. Keep this manual and purchase receipt for warranty claims.

Troubleshooting

Service: For repairs beyond basic maintenance, contact authorized Husqvarna dealer.

Support: 1-800-487-5962; www.husqvarna.com