Husky 51 Chainsaw Manual

The Husky 51 Chainsaw is a professional-grade gasoline-powered chainsaw designed for demanding cutting tasks. It features a high-performance engine, automatic chain oiling system, anti-vibration handles, inertia-activated chain brake, and easy-start technology. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: High-torque 2-stroke engine, 16-20 inch guide bar, automatic chain oiler, anti-vibration system, inertia chain brake, side-access chain tensioner.

Feature	Description
Engine Type	2-stroke, air-cooled gasoline engine
Displacement	51cc
Guide Bar Length	16-20 inches (standard 18")
Chain Pitch	3/8" low-profile
Automatic Oiler	Delivers oil to bar and chain during operation
Anti-Vibration	Reduced vibration handles for comfort
Chain Brake	Inertia-activated safety brake
Fuel Tank Capacity	14.9 fl oz (440 ml)
Oil Tank Capacity	8.5 fl oz (250 ml)
Weight (without bar/chain)	10.8 lbs (4.9 kg)

Assembly & Setup

Unpack and inspect all components. Assemble on a clean, flat surface.

1. Attach guide bar and chain: Place bar on mounting studs, fit chain around sprocket and bar groove, adjust tension.
2. Fill fuel tank: Mix high-quality 2-stroke oil with unleaded gasoline (50:1 ratio).
3. Fill chain oil tank: Use recommended bar and chain oil.
4. Check controls: Ensure throttle trigger, choke, and stop switch operate smoothly.

WARNING! Always wear protective gloves when handling chain. Ensure chain is properly tensioned before use.

Safety Instructions

Read all safety warnings before operation.

1. Personal Protective Equipment: Always wear safety glasses, hearing protection, gloves, chainsaw chaps, and steel-toe boots.
2. Clear work area: Remove tripping hazards and ensure bystanders are at least 15 feet away.
3. Check chain brake: Test inertia brake before each use.
4. Fuel safety: Refuel outdoors, away from ignition sources; wipe spills immediately.

CAUTION! Never operate chainsaw above shoulder height or with one hand. Kickback can cause serious injury.

Specifications

• Model: Husky 51
• Engine Power: 3.2 HP
• Max Power Speed: 9,500 RPM
• Idle Speed: 2,700 RPM
• Fuel Mix Ratio: 50:1 (unleaded gasoline to 2-stroke oil)
• Ignition System: Electronic, capacitor discharge
• Spark Plug: Champion RCJ7Y or equivalent
• Sound Level: 105 dB(A) at operator's ear
• Vibration Level: Front handle: 4.2 m/s²; Rear handle: 5.1 m/s²
• Warranty: 2 years commercial, 5 years consumer

Controls and Components

Main controls located on top and rear handle.

Top Handle: Chain brake lever, throttle trigger lockout, choke control, stop switch.

Rear Handle: Throttle trigger, rear hand guard.

Side Panel: Side-access chain tensioner, combined choke/stop control.

Fuel System: Fuel tank cap, primer bulb, air filter cover.

Maintenance Points: Spark plug, cylinder cover, chain catcher, muffler.

Starting & Operation

Cold Start Procedure:

1. Place chainsaw on flat ground, clear of debris.
2. Engage chain brake by pushing forward.
3. Set choke to full position (cold engine).
4. Press primer bulb 5-6 times.
5. Pull starter rope briskly until engine fires.
6. Move choke to half position, pull until engine starts.
7. Allow to warm up 30 seconds before releasing chain brake.

Tip: Always hold rear handle with right hand, front handle with left hand. Maintain secure footing.

Chain & Bar Maintenance

Regular maintenance ensures optimal performance and safety.

1. Chain tension: Check frequently; chain should snap back when pulled from bar.
2. Sharpening: Use round file matching chain pitch; maintain 30° cutting angle.
3. Bar maintenance: Clean bar groove weekly; flip bar monthly for even wear.
4. Oiler test: Run at high idle over cardboard; should produce fine oil line.
5. Sprocket inspection: Replace if worn or damaged.

WARNING! Always disconnect spark plug before performing chain maintenance.

Engine Maintenance

Air filter: Clean weekly with soapy water; replace if damaged.

Spark plug: Clean and regap (0.020") every 25 hours; replace annually.

Fuel filter: Replace every 100 hours or annually.

Carburetor adjustment: Factory set; only adjust if necessary using H and L screws.

Muffler: Clean spark arrestor screen monthly.

Storage Guidelines

Long-term storage preparation:

1. Drain fuel tank and run engine until it stops.
2. Remove spark plug, add 1 teaspoon of oil through spark plug hole.
3. Pull starter rope slowly to distribute oil.
4. Clean entire chainsaw, especially cooling fins.
5. Store in dry place, cover to prevent dust.

CAUTION! Never store with fuel in tank for more than 30 days. Use fuel stabilizer if needed.

Warranty Information

Husqvarna provides 2-year commercial warranty and 5-year consumer warranty from date of purchase. Warranty covers defects in materials and workmanship. Not covered: normal wear, misuse, improper maintenance, or use of non-genuine parts. Keep original receipt. For warranty claims, contact authorized Husqvarna dealer or call 1-800-487-5962. Register product at www.husqvarna.com.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No spark, fuel issues, flooded	Check spark plug; ensure fresh fuel; wait if flooded; check air filter.
Engine starts then dies	Clogged fuel filter, carburetor issues	Replace fuel filter; clean carburetor; check fuel line.
Chain doesn't turn	Brake engaged, clutch worn, sprocket	Disengage chain brake; inspect clutch and sprocket; adjust chain tension.
Excessive vibration	Loose components, unbalanced chain	Tighten all bolts; balance chain; check anti-vibration mounts.
Chain throws oil	Over-oiling, wrong oil viscosity	Adjust oiler screw; use correct bar oil; clean oil passages.
Poor cutting performance	Dull chain, wrong filing angle	Sharpen chain properly; check depth gauges; ensure proper tension.

Service Intervals: Professional servicing recommended every 100 operating hours.

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