Oregon 91 Chainsaw Manual

The Oregon 91 Chainsaw is a professional-grade chainsaw designed for demanding cutting tasks, featuring a high-performance engine, automatic chain oiling system, safety chain brake, ergonomic handles, and low-vibration technology. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: High-torque engine, Automatic chain oiler, Safety chain brake, Ergonomic front and rear handles, Anti-vibration system, Quick-stop inertia brake.

Safety Information

Always wear proper safety gear and follow operating procedures.

1. Personal Protective Equipment: Wear safety glasses, hearing protection, gloves, chainsaw chaps, and steel-toe boots.
2. Pre-Operation Check: Inspect chain tension, sharpness, and lubrication before each use.
3. Clear Work Area: Ensure no obstacles, bystanders, or animals within 15 feet.
4. Proper Stance: Maintain secure footing with feet shoulder-width apart.

WARNING! Never operate chainsaw with one hand. Keep both hands on handles at all times. Avoid kickback zone (upper quadrant of guide bar tip).

Assembly & Setup

Unpack and inspect all components. Assemble according to instructions.

1. Attach Guide Bar and Chain: Place bar on mounting studs, fit chain with cutters facing forward, adjust tension.
2. Fill Fuel Tank: Mix 50:1 gasoline with 2-stroke oil (89 octane minimum).
3. Fill Chain Oil Tank: Use Oregon chain and bar oil or equivalent.
4. Check Controls: Ensure throttle trigger, throttle lockout, and chain brake function properly.

CAUTION! Fuel is highly flammable. Refuel in well-ventilated area with engine off and cool.

Specifications

• Engine Displacement: 91 cc (5.55 cu in).
• Power Output: 6.5 hp at 9,000 RPM.
• Idle Speed: 2,800 RPM.
• Maximum Power Speed: 10,500 RPM.
• Fuel Consumption: Approx. 1.1 L/h at full load.
• Sound Pressure Level: 112 dB(A) at operator's ear.
• Vibration Level: Front handle 4.2 m/s², rear handle 5.8 m/s².
• Ignition System: Electronic, capacitor discharge.
• Carburetor: Walbro diaphragm with adjustable H and L jets.
• Recommended Fuel: Unleaded gasoline 89 octane minimum.

Controls and Functions

Main Controls: Front handle with throttle trigger, Rear handle with throttle lockout, Chain brake lever, Choke control, Primer bulb, Master control lever (stop switch).

Operation Sequence: Set chain brake to ON, Pull choke, Press primer 5-6 times, Set master control to cold start, Pull starter rope until engine fires, Push choke in, Pull starter rope to start, Release chain brake before cutting.

Adjustments: Chain tension (side tensioner), Idle speed (screw T), High/Low carburetor jets (H and L screws), Oil flow rate (adjustment screw near oil tank).

Operation Guide

Starting Procedure: Follow cold/hot start instructions. Cutting Techniques: Use lower quadrant of bar, maintain steady throttle, let chain do the work.

1. Bucking: Cut fallen logs from top side, support log properly.
2. Limbing: Work from trunk outward, keep saw stable.
3. Felling: Plan escape path, make notch cut 1/3 diameter, make felling cut leaving hinge.
4. Kickback Prevention: Maintain firm grip, avoid tip contact, use reduced-kickback chain.

Tip: Keep chain sharp for efficient cutting and reduced operator fatigue.

Maintenance Schedule

Daily: Clean air filter, check chain tension and sharpness, inspect bar for wear. Weekly: Clean spark arrestor screen, check spark plug, clean cooling fins. Monthly: Replace fuel filter, clean carburetor, check all fasteners. Seasonally: Replace spark plug, clean fuel tank, inspect anti-vibration elements.

1. Air Filter: Clean with soapy water, dry completely, re-oil lightly.
2. Spark Plug: Clean electrodes, adjust gap to 0.020" (0.5 mm).
3. Chain Tension: Adjust when chain sags from bar rails.
4. Bar Maintenance: File rails, clean oil holes, rotate bar regularly.

WARNING! Perform maintenance only when engine is off and cool. Disconnect spark plug wire for safety.

Chain Sharpening

Use Oregon filing kit (file size 7/32" for 3/8" chain).

1. Secure Bar: Clamp bar in vise.
2. File Angle: Maintain 30° cutting angle.
3. File Depth: Keep file level with top plate.
4. File Pressure: Light, even strokes away from body.
5. Depth Gauges: File to 0.025" (0.65 mm) below cutter.
6. Equal Strokes: Same number of strokes per cutter.

CAUTION! Wear gloves when handling chain. File in one direction only.

Storage Guidelines

Long-term Storage: Drain fuel tank and run engine dry. Remove chain and clean. Store in dry, secure location.

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

Warranty Information

Oregon 91 Chainsaw comes with 2-year commercial warranty and 5-year consumer warranty. Warranty covers defects in materials and workmanship. Not covered: Normal wear, misuse, improper maintenance, unauthorized repairs. For warranty claims, contact authorized Oregon dealer with proof of purchase. For support, visit www.oregonproducts.com or contact 1-800-223-5168.

Troubleshooting

Service: 1-800-223-5168; www.oregonproducts.com