McCulloch 838 Chainsaw Manual

The McCulloch 838 is a professional-grade gasoline chainsaw designed for heavy-duty cutting tasks. It features a powerful engine, automatic chain oiling, anti-vibration system, safety 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-performance 2-stroke engine, 20-inch guide bar, automatic oiler, chain brake, decompression valve, anti-vibration handles, and easy-access air filter.

Feature	Description
Engine Displacement	83.8 cc professional-grade engine
Guide Bar Length	20 inches (standard)
Chain Type	.404 pitch, safety chain with kickback reduction
Automatic Oiler	Delivers oil to bar and chain during operation
Chain Brake	Inertia-activated safety feature to stop chain
Anti-Vibration System	Reduces operator fatigue during extended use
Decompression Valve	Reduces starting resistance for easier pull-starts
Air Filtration	Dual-stage air filter for engine protection
Fuel Capacity	Approximately 24 oz (710 ml) fuel tank
Oil Capacity	Approximately 12 oz (355 ml) oil tank

Safety Instructions

Read all instructions before operation. Always wear appropriate PPE.

1. Personal Protective Equipment (PPE): Always wear safety glasses, hearing protection, gloves, chainsaw chaps/pants, and steel-toe boots.
2. Work Area Safety: Clear area of bystanders, especially children and pets. Ensure secure footing.
3. Pre-Operation Check: Inspect chainsaw for damage, loose parts, proper chain tension, and sharpness before each use.
4. Fuel Safety: Refuel in well-ventilated area with engine off and cool. Use proper fuel/oil mix (50:1).

WARNING! Kickback can occur without warning. Always hold saw firmly with both hands. Never operate above shoulder height or with one hand.

Assembly & Preparation

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

1. Attach Guide Bar & Chain: Place bar on mounting studs. Loop chain over sprocket and onto bar groove, ensuring cutting teeth face forward on top. Adjust tension.
2. Fill Fuel Tank: Use fresh unleaded gasoline (minimum 89 octane) mixed with 2-cycle oil at 50:1 ratio. Shake container thoroughly before filling.
3. Fill Oil Tank: Use high-quality bar and chain oil. Do not use waste oil.
4. Check Controls: Ensure throttle trigger, throttle lockout, and chain brake function properly.

CAUTION! Chain must be properly tensioned—snug against bar but able to be pulled around by hand.

Specifications

• Model: McCulloch 838
• Engine Type: 2-stroke, air-cooled
• Displacement: 83.8 cc
• Power Output: 5.2 HP
• Fuel/Oil Ratio: 50:1 (unleaded gasoline to 2-cycle oil)
• Guide Bar Length: 20 inches (50.8 cm)
• Chain Pitch: .404 inch
• Chain Gauge: .063 inch
• Dry Weight: 15.4 lbs (7.0 kg) without bar and chain
• Sound Pressure Level: 112 dB(A) at operator's ear
• Vibration Level: Front handle: 4.5 m/s²; Rear handle: 5.2 m/s²

Controls and Components

Familiarize yourself with all controls before starting the engine.

Main Controls:

• Throttle Trigger: Controls engine speed. Release to idle.
• Throttle Lockout: Must be depressed before throttle can be engaged (safety feature).
• Chain Brake Lever: Manually engage brake by pushing forward. Inertia will activate it during kickback.
• Decompression Valve Button: Press before starting to reduce cylinder pressure.
• Choke Control: Used for cold starts.
• Master Control Lever: Combines choke/stop functions (OFF, RUN, CHOKE).
• Front Hand Guard: Protects left hand and activates inertia chain brake.
• Oil Pump Adjustment Screw: Adjusts flow rate of automatic oiler (if equipped).

Starting & Stopping Procedure

Always start on ground or solid surface. Never drop-start.

Cold Start:

1. Engage chain brake.
2. Set master control lever to CHOKE position.
3. Press decompression valve (if equipped).
4. Place saw on ground, hold front handle with left hand, place right foot through rear handle.
5. Pull starter rope briskly 3-5 times until engine "pops".
6. Move master control lever to RUN position.
7. Pull starter rope again until engine starts.
8. Blip throttle to disengage fast idle. Release chain brake.

Warm Start: Master control lever in RUN position. No choke needed.

Stopping: Release throttle, allow engine to idle briefly. Move master control lever to OFF position.

Operation & Cutting Techniques

Always use proper cutting stance and techniques to maintain control.

1. Basic Stance: Feet shoulder-width apart, left foot slightly forward. Hold saw close to body with arms slightly bent.
2. Bucking (cutting felled logs): Support log off ground. Cut from top down. Watch for binding; use wedges if needed.
3. Limbing: Stand on opposite side of tree from branches. Let saw do the work; avoid pushing chain into cut.
4. Notching & Felling: For trained users only. Use proper notch (70-80% of tree diameter) and back cut. Plan escape path.
5. Kickback Prevention: Keep saw body close to wood. Do not let bar nose contact wood, especially upper quadrant.

WARNING! Never cut with the tip of the bar. This is the primary kickback danger zone.

Maintenance Schedule

Interval	Task
Before each use	Check chain tension, sharpness, and lubrication. Inspect for loose fasteners.
Daily (or every 5 hours)	Clean air filter. Check spark plug condition.
Weekly (or every 25 hours)	Clean cooling fins. Check fuel filter. Clean spark arrestor screen (if equipped).
Monthly (or every 100 hours)	Replace air filter. Clean carburetor air intake. Inspect bar for wear and damage.
Annually (or every 500 hours)	Replace fuel filter. Clean/replace spark plug. Have professional check carburetor adjustment and compression.

Note: Maintenance frequency increases with heavy use or dirty conditions.

Chain Sharpening & Tensioning

A sharp, properly tensioned chain is essential for safety and performance.

Sharpening:

1. Secure bar in vise. File at angle specified on chain (typically 30°-35°).
2. Use correct round file size (.404 chain uses 5/32" file).
3. File from inside out, maintaining equal pressure on all cutting teeth.
4. File depth gauges (rakers) with flat file and gauge to maintain proper height difference.

Tensioning:

1. Loosen bar nuts.
2. Turn tensioning screw until chain is snug against bar but can be pulled around by hand.
3. Retighten bar nuts while lifting tip of bar.
4. Re-check tension after running saw for 30 seconds; chain stretches when warm.

Storage Guidelines

Proper storage prevents fuel system issues and corrosion.

1. Short-term (less than 30 days): Run carburetor dry or add fuel stabilizer to tank. Run engine for 2 minutes to circulate treated fuel.
2. Long-term (over 30 days): Drain fuel tank completely. Run engine until it stops to empty carburetor. Remove chain, clean and oil it. Store in dry place.
3. Clean entire saw, especially cooling fins and air filter area.
4. Store chain and bar separately in oiled cloth.

CAUTION! Never store saw with fuel in tank for extended periods. Old fuel can gum up carburetor.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine will not start	No spark, flooded, old fuel, clogged filter	Check spark plug; use fresh fuel mix; clean air filter; wait if flooded.
Engine starts then dies	Clogged fuel filter, carburetor issues	Replace fuel filter; clean carburetor; check fuel line.
Chain does not turn	Chain brake engaged, clutch worn, sprocket damaged	Disengage brake; inspect clutch and sprocket; replace if worn.
Chain throws oil but doesn't cut	Dull chain, improper filing	Sharpen chain correctly; check depth gauge height.
Excessive vibration	Loose components, unbalanced chain, damaged AV mounts	Tighten all fasteners; balance chain; inspect anti-vibration mounts.
Chain comes off bar	Loose bar nuts, worn bar, improper tension	Tighten bar nuts; inspect bar groove; replace if worn; adjust tension.

Service: For major repairs, contact authorized McCulloch service center. Use only genuine McCulloch parts.

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