Husqvarna 450 Chainsaw Manual

The Husqvarna 450 is a professional-grade chainsaw featuring a 50.2cc X-Torq engine for reduced emissions and fuel consumption, Smart Start for easy starting, Air Injection centrifugal air cleaning system, LowVib anti-vibration system, combined choke/stop control, inertia-activated chain brake, and side-mounted chain tensioning. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: X-Torq engine, Air Injection system, Smart Start, LowVib handles, combined choke/stop control, side chain tensioner, inertia chain brake.

Safety Information

Read all instructions before operation. Wear proper protective equipment.

1. Personal Protective Equipment: Always wear safety glasses, hearing protection, gloves, chainsaw chaps, and steel-toed boots.
2. Work Area Safety: Clear area of bystanders, especially children. Ensure secure footing.
3. Fuel Safety: Refuel in well-ventilated area with engine stopped and cool. Use fuel mix 50:1 (2-stroke oil to unleaded gasoline).
4. Kickback Awareness: Be aware of kickback zone (upper quadrant of bar tip). Use reduced-kickback chain and maintain proper chain tension.

WARNING! Chainsaws are dangerous tools. Failure to follow safety instructions can result in serious injury or death.

Assembly & Preparation

Unpack and inspect contents. Assemble before first use.

1. Attach guide bar and chain: Place bar on studs, fit chain around sprocket and bar, adjust tension with side screw.
2. Fill chain oil tank: Use recommended bar and chain oil. Check oil level before each use.
3. Prepare fuel mix: Use 50:1 ratio of unleaded gasoline (minimum 89 octane) and Husqvarna 2-stroke oil.
4. Check all fasteners: Ensure all nuts, bolts, and screws are tight before operation.

CAUTION! Never operate without proper chain tension and lubrication.

Specifications

• Engine Displacement: 50.2cc
• Power Output: 3.2 HP
• Fuel Tank Volume: 0.95 US pint (0.45 liter)
• Oil Tank Volume: 0.63 US pint (0.30 liter)
• 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 Power Level: 114 dB(A)
• Vibration Levels: Front handle: 3.2 m/s², Rear handle: 4.5 m/s²

Controls and Components

Main components: Front handle with throttle trigger and lockout, rear handle, choke/stop control, primer bulb, chain brake, chain tensioner.

Controls: Throttle trigger with lockout (prevents accidental acceleration), combined choke/stop control (positions: run, choke, stop), primer bulb (press 6-10 times for cold start), chain brake handle (manual activation), inertia brake (automatic), decompression valve (reduces starting effort).

Maintenance points: Air filter cover, spark plug, cylinder cover, chain catcher, muffler, fuel and oil caps.

Starting & Stopping

Cold Start Procedure:

1. Place chainsaw on flat ground, clear of debris.
2. Activate chain brake by pulling handle toward front handle.
3. Set choke/stop control to choke position (full up).
4. Press primer bulb 6-10 times until fuel is visible.
5. Pull starter handle until engine fires (usually 3-5 pulls).
6. Move choke/stop control to run position (middle).
7. Pull starter handle again until engine starts.
8. Release chain brake before cutting.

Warm Start: Skip steps 3 and 6. Use run position only.

Stopping: Release throttle, move choke/stop control to stop position.

Operating Instructions

Proper cutting techniques for safety and efficiency.

1. Basic stance: Stand with feet shoulder-width apart, left foot slightly forward.
2. Grip: Hold front handle with left hand, rear handle with right hand. Thumbs wrapped around handles.
3. Starting cut: Apply light pressure, let chain do the work. Avoid forcing the saw.
4. Kickback prevention: Never cut with upper quadrant of bar tip. Be aware of pinch points.
5. Bucking: Support log properly. Cut from top down for supported logs, undercut first for unsupported.
6. Limbing: Work from trunk outward. Beware of springback from tensioned branches.

Tip: Maintain sharp chain and proper tension for optimal performance.

Maintenance Schedule

Regular maintenance ensures longevity and safe operation.

Chain & Bar Care

Proper chain maintenance is critical for performance and safety.

1. Sharpening: Use round file matching chain pitch (usually 5/32" for 3/8" chain). Maintain 30° cutting angle. File all cutters evenly.
2. Tensioning: Chain should snap back when pulled from bar. Adjust when chain sags from bottom of bar.
3. Bar maintenance: Clean bar groove regularly. Flip bar monthly for even wear. Dress bar rails if burred.
4. Lubrication: Always use recommended bar and chain oil. Check oil flow by pointing at light surface while running.

CAUTION! Always wear gloves when handling chain. Disconnect spark plug wire during maintenance.

Storage Guidelines

Proper storage prevents fuel system issues and corrosion.

1. Short-term (under 30 days): Fill fuel tank with fresh mix, run engine briefly to circulate treated fuel.
2. Long-term (over 30 days): Drain fuel tank completely. Run engine until it stops to clear carburetor. Remove chain and store in oil.
3. General: Clean entire saw. Store in dry place, protected from moisture. Cover to prevent dust accumulation.
4. Fuel storage: Never store fuel mix more than 30 days. Use fuel stabilizer if needed.

WARNING! Never store with fuel in tank for extended periods - gumming will occur.

Troubleshooting

Service: For complex repairs, contact authorized Husqvarna dealer.

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