GMC Chainsaw Manual

The GMC Chainsaw is a powerful and reliable tool designed for cutting wood, pruning trees, and general forestry work. It features a high-performance engine, automatic chain oiling, anti-vibration system, safety chain brake, and ergonomic handles for comfortable operation. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Engine, guide bar, cutting chain, chain brake, throttle trigger, choke control, fuel tank, oil tank, and safety features.

Feature	Description
Engine Type	2-stroke gasoline engine
Guide Bar Length	Available in 14", 16", 18" sizes
Chain Brake	Automatic inertia-activated safety brake
Anti-Vibration System	Reduces operator fatigue
Automatic Oiling	Continuous chain lubrication
Safety Throttle Lock	Prevents accidental throttle engagement
Ergonomic Handles	Rubber-coated for secure grip
Chain Tensioning	Tool-free adjustment system
Fuel Mix Ratio	50:1 (Gasoline to 2-stroke oil)
Spark Arrestor	Prevents emission of burning particles

Safety Instructions

Read all instructions before operation. Always wear appropriate safety gear.

1. Personal Protective Equipment: Wear safety glasses, hearing protection, gloves, steel-toe boots, and chainsaw chaps.
2. Work Area Safety: Clear area of obstacles, ensure secure footing, keep bystanders away.
3. Chain Safety: Always engage chain brake when not cutting, keep chain sharp and properly tensioned.
4. Fuel Safety: Refuel in well-ventilated area, away from ignition sources, with engine off and cool.

WARNING! Never operate chainsaw with one hand. Always maintain firm grip with both hands. Beware of kickback.

Assembly & Preparation

Unpack and inspect all components. Assemble according to instructions.

1. Attach Guide Bar & Chain: Place bar on mounting studs, fit chain around bar sprocket, adjust tension.
2. Fill Fuel Tank: Mix gasoline and 2-stroke oil (50:1 ratio). Use fresh fuel.
3. Fill Oil Tank: Use quality bar and chain oil. Check oil level before each use.
4. Check Controls: Ensure throttle trigger, throttle lock, and chain brake function properly.

CAUTION! Ensure all fasteners are tight. Do not operate with loose components.

Specifications

• Engine Displacement: 45cc to 55cc (model dependent).
• Power Output: 2.5 HP to 3.2 HP.
• Fuel Capacity: 0.5 to 0.7 liters.
• Oil Capacity: 0.25 to 0.35 liters.
• Weight: 4.5 kg to 5.5 kg (without fuel and oil).
• Chain Pitch: 3/8" or 0.325".
• Chain Gauge: 0.050" or 0.058".
• Ignition System: Electronic ignition.
• Sound Level: Approximately 105 dB(A).
• Vibration Level: Less than 2.5 m/s².

Controls and Components

Main Controls: Throttle trigger, throttle lockout, choke control, stop switch, chain brake handle.

Components: Front handle, rear handle, muffler, spark plug, air filter, fuel cap, oil cap, chain catcher, hand guard.

Operation: Pull choke for cold start, push choke to run position. Squeeze throttle lockout and trigger to accelerate. Push stop switch to stop engine. Pull hand guard toward front handle to engage chain brake.

Starting & Stopping

Starting Procedure (Cold Engine):

1. Place chainsaw on flat, clear ground.
2. Engage chain brake by pulling hand guard forward.
3. Set choke lever to full choke position.
4. Press decompression valve (if equipped).
5. Pull starter rope briskly until engine fires.
6. Move choke to half-throttle position.
7. Pull starter rope again until engine starts.
8. Allow engine to warm up for 30 seconds before disengaging chain brake.

Stopping: Release throttle, allow engine to idle, push stop switch to OFF position.

Operating Instructions

Basic Cutting Techniques:

1. Felling Trees: Plan escape path, make notch cut, then felling cut. Use wedges if needed.
2. Limbing: Cut branches from fallen tree, work from trunk to top, keep saw close to trunk.
3. Bucking: Cut log into sections, support log properly, avoid pinching chain.
4. Pruning: Cut small branches with pulling chain (bottom of bar), support branch being cut.

Kickback Prevention: Hold saw firmly, do not cut with tip of bar, maintain chain sharpness, use reduced-kickback chain.

Maintenance & Cleaning

Daily Maintenance:

1. Clean air filter: Remove, wash in soapy water, dry thoroughly.
2. Check chain tension: Adjust when chain sags from guide bar.
3. Inspect chain sharpness: Sharpen when cutting becomes difficult.
4. Clean cooling fins and muffler area of debris.
5. Check all nuts and bolts for tightness.

Weekly Maintenance: Clean spark arrestor, check spark plug gap (0.025"), clean fuel filter, inspect anti-vibration elements.

Chain Sharpening & Replacement

Sharpening Procedure:

1. Secure guide bar in vise.
2. Use round file matching chain pitch (5/32" for 3/8" chain).
3. File each cutter at 30° angle, maintain consistent pressure.
4. File depth gauges with flat file to proper height (0.025" below cutter).
5. Sharpen all cutters to same length.

Chain Replacement: When cutters are worn beyond repair or chain is damaged. Always replace with GMC-approved chain matching guide bar specifications.

Storage Guidelines

Long-Term Storage (Over 30 days):

1. Drain fuel tank completely.
2. Run engine until it stops to clear carburetor.
3. Remove spark plug, add 1 teaspoon of oil through spark plug hole, pull starter 2-3 times, reinstall plug.
4. Clean entire chainsaw thoroughly.
5. Remove chain, clean and soak in oil, store in sealed bag.
6. Store in dry, cool place away from children.

CAUTION! Never store with fuel in tank. Fuel deteriorates and can damage engine components.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No fuel, flooded engine, spark plug	Check fuel level, wait if flooded, clean/replace spark plug.
Engine starts then dies	Clogged fuel filter, air filter	Replace fuel filter, clean air filter.
Chain doesn't turn	Chain brake engaged, clutch worn	Disengage chain brake, inspect clutch assembly.
Chain oil not flowing	Empty oil tank, clogged oil hole	Fill oil tank, clean oil passageways.
Excessive vibration	Loose components, unbalanced chain	Tighten all fasteners, balance chain or replace.
Poor cutting performance	Dull chain, improper tension	Sharpen chain, adjust tension correctly.
Engine overheats	Dirty cooling fins, lean fuel mixture	Clean cooling fins, adjust carburetor.

Service: For technical support, contact GMC Customer Service at 1-800-123-4567 or visit www.gmctools.com