McCulloch Pro Mac 650 Chainsaw Manual

The McCulloch Pro Mac 650 is a professional-grade chainsaw featuring a powerful 65cc 2-stroke engine, automatic oiling system, anti-vibration handles, chain brake, and a 20-inch guide bar. Designed for demanding cutting tasks, it includes safety features, maintenance guidelines, and operational instructions. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: 65cc 2-stroke engine, 20-inch guide bar, automatic chain oiler, anti-vibration system, chain brake, decompression valve, primer bulb, and safety throttle lock.

Safety Instructions

Read all instructions before operation. Wear protective gear.

1. Personal Protective Equipment: Always wear safety glasses, hearing protection, gloves, chainsaw chaps, and steel-toe boots.
2. Work Area Safety: Clear area of bystanders, especially children. Ensure secure footing.
3. Fuel Safety: Refuel outdoors, away from ignition sources. Use fuel/oil mix (50:1).
4. Kickback Awareness: Hold saw firmly; avoid tip contact. Use reduced-kickback chain.

WARNING! Chainsaw can cause severe injury or death. Never operate when tired or under influence. Always engage chain brake when carrying.

Assembly & Setup

Unpack and inspect contents. Assemble guide bar and chain.

1. Attach Guide Bar: Loosen bar nuts, position bar over studs, align chain drive links with sprocket.
2. Install Chain: Place chain over bar, ensuring cutting teeth face forward on top.
3. Tension Chain: Adjust tensioning screw until chain snaps back when pulled from bar.
4. Fill Fluids: Add fuel mix (50:1 2-stroke oil/gasoline) to fuel tank. Fill chain oil reservoir.
5. Priming: Press primer bulb 5-6 times until fuel is visible.

CAUTION! Ensure chain is properly tensioned—too loose may derail; too tight may damage bar.

Specifications

• Engine: 65cc 2-stroke, air-cooled.
• Power Output: 4.2 HP @ 9000 RPM.
• Fuel: Unleaded gasoline (min 89 octane) with 2-stroke oil (50:1 ratio).
• Bar Length: 20 inches (50.8 cm).
• Chain Pitch: 0.375 inches (3/8").
• Chain Gauge: 0.050 inches.
• Drive Links: 72 DL.
• Idle Speed: 2800 RPM.
• Max RPM: 12,500 RPM.
• Sound Level: 105 dB(A) at operator's ear.

Controls and Functions

Main Controls: Throttle trigger, throttle lockout, choke, ON/OFF switch, primer bulb, decompression valve.

Right Side: Throttle trigger, throttle lockout (safety), hand guard/chain brake. Left Side: Choke control, decompression valve, primer bulb. Rear: ON/OFF switch. Front: Chain tensioning screw, bar nuts.

Chain Brake: Engage manually by pushing hand guard forward; automatically engages on kickback. Decompression Valve: Reduces compression for easier starting. Primer Bulb: Pumps fuel into carburetor for cold starts.

Operation Guide

Starting Procedure (Cold Engine):

1. Place saw on level ground, clear of debris.
2. Engage chain brake.
3. Move ON/OFF switch to ON.
4. Pull choke to FULL position.
5. Press primer bulb 5-6 times.
6. Press decompression valve (if equipped).
7. Hold front handle with left hand, place right foot in rear handle.
8. Pull starter cord briskly until engine fires.
9. Push choke to HALF, pull until engine starts.
10. Blip throttle to disengage choke.

Cutting Techniques: Use lower quadrant of bar for cutting; avoid tip contact. Let saw do the work—do not force.

Maintenance Schedule

Air Filter: Remove, tap clean, or wash in soapy water if foam. Spark Plug: Gap 0.025 inches (0.63 mm).

Chain Sharpening & Tensioning

Sharpening: Use round file (7/32" or 5.5 mm) and file guide.

1. Secure bar in vise.
2. Place file guide over chain, match file angle (typically 30°).
3. File each cutter with smooth forward strokes; maintain equal strokes per cutter.
4. Check depth gauges with gauge tool; file if above limit.

Tensioning: Loosen bar nuts, turn tensioning screw clockwise until chain is snug against bar bottom. Chain should pull freely but not sag. Tighten bar nuts.

Tip: Rotate bar periodically for even wear.

Storage Guidelines

For long-term storage (over 30 days):

1. Drain fuel tank and run engine until it stops.
2. Remove spark plug, add 1 tsp of 2-stroke oil into cylinder, pull starter 2-3 times, reinstall plug.
3. Clean entire saw, especially cooling fins and air filter.
4. Remove chain, clean and soak in oil; store separately.
5. Store in dry, cool place, covered.

CAUTION! Never store with fuel in tank—fuel may degrade and damage carburetor.

Warranty Information

McCulloch Pro Mac 650 includes a 2-year limited warranty for residential use and a 90-day warranty for commercial use. Warranty covers defects in materials/workmanship. Not covered: normal wear, misuse, lack of maintenance, improper fuel. Proof of purchase required. For warranty claims, contact authorized service center or call 1-800-521-8559. Visit www.mcculloch.com for details.

Troubleshooting

Service: For repairs, use authorized McCulloch service centers. DIY repairs may void warranty.

Support: 1-800-521-8559; www.mcculloch.com