McCulloch 250 Chainsaw Manual

The McCulloch 250 is a classic, powerful chainsaw designed for heavy-duty cutting tasks. This manual covers essential safety procedures, technical specifications, assembly instructions, operation guidelines, routine maintenance, troubleshooting, and parts information. Always read and understand this manual completely before operating the saw to ensure safe and effective use.

Safety Information & Warnings

Operating a chainsaw is inherently dangerous. Failure to follow safety instructions can result in serious injury or death.

WARNING! Never operate a chainsaw when tired, under the influence of medication, drugs, or alcohol. Keep bystanders and pets at a safe distance.

Specifications & Features

• Model: McCulloch 250
• Engine Type: 2-stroke, air-cooled gasoline engine
• Displacement: Approximately 3.3 cu. in. (54cc)
• Fuel Capacity: ~ 0.6 US qt (0.57 L)
• Oil Capacity: ~ 0.3 US qt (0.28 L)
• Bar Length: Typically 16" to 20" (check guide bar marking)
• Chain Pitch/Gauge: .404" pitch, .063" gauge (common)
• Ignition System: Electronic (solid-state)
• Weight: Approximately 14.5 lbs (6.6 kg) dry
• Features: Manual oiler, automatic chain oiler, anti-vibration handles, chain brake (on some models).

Assembly & Initial Setup

Assemble your chainsaw on a clean, flat surface.

1. Attach Guide Bar & Chain: Place the chain on the bar, ensuring cutting teeth face forward on top. Fit the bar onto the studs, aligning the tensioning pin. Loop the chain around the drive sprocket. Install the side cover and tighten nuts finger-tight.
2. Tension Chain: Lift the bar tip up. Using the tensioning screw, adjust until the chain fits snugly against the bar but can be pulled around by hand. Tighten side cover nuts securely.
3. Fill Fluids: Add the correct fuel/oil mix to the fuel tank. Fill the chain oil reservoir with approved bar and chain oil.

CAUTION! Do not attempt to start the saw until assembly is complete and chain tension is correctly set. A loose chain can derail; an overtightened chain can damage the engine.

Controls & Components

Familiarize yourself with all controls before starting.

Fuel & Oil Mixture

The McCulloch 250 uses a 2-stroke engine requiring a gasoline and oil mixture.

• Fuel: Use fresh, unleaded gasoline with a minimum octane rating of 89 (R+M)/2.
• Oil: Use a high-quality 2-stroke engine oil designed for air-cooled engines at a 50:1 ratio (check manual sticker for confirmation).
• Mix Ratio Example: 2.6 US fl oz of oil per 1 US gallon of gasoline.
• Chain Oil: Use a dedicated bar and chain oil for proper lubrication. Do not use waste oil.

WARNING! Never use straight gasoline or automotive motor oil. Improper mixture will cause severe engine damage. Mix fuel in an approved container, not in the saw's tank.

Starting & Stopping Procedure

Cold Start:

1. Place saw on firm, level ground. Engage chain brake.
2. Set master control lever to CHOKE (or pull choke knob out).
3. Press decompression valve (if equipped).
4. Pump primer bulb 5-10 times (if equipped).
5. Place your right foot through the rear handle and hold the front handle down firmly with your left hand.
6. Pull starter rope briskly until engine 'pops' (fires once).
7. Move control lever to FAST IDLE/HALF CHOKE position.
8. Pull starter rope again until engine starts.
9. Blip the throttle to disengage fast idle. Allow to warm up for 30 seconds.

Warm Start: Set control lever to RUN/START position and pull.

Stopping: Release throttle to idle. Move master control lever to STOP position.

Operating Instructions

1. Stance & Grip: Stand with feet shoulder-width apart for balance. Grip handles firmly with thumbs and fingers wrapped around.
2. Cutting: Let the saw do the work. Use full throttle just before and during the cut. Do not force the saw.
3. Kickback Zone: Avoid contact with the upper quarter of the guide bar tip.
4. Manual Oiling: Press the manual oiler button frequently during cutting, especially in dry or dirty conditions.
5. Carrying: Always engage the chain brake when carrying the saw more than a few steps or over obstacles.

Tip: Plan your cuts and escape path before starting, especially when felling trees.

Routine Maintenance

Perform these checks before each use:

Chain Sharpening & Tensioning

A sharp chain is essential for safety and performance.

1. Sharpen: Use a round file matching your chain's pitch (e.g., 7/32" for .404" pitch). File each cutter at the manufacturer's specified angle (typically 30°). Maintain equal file strokes per cutter. File depth gauges (rakers) with a flat file and gauge.
2. Tension: Chain should be snug against the bar but pull freely by hand. Re-tension when chain is warm after a few minutes of use. A properly tensioned chain will not sag from the bar underside.

CAUTION! Always wear heavy gloves when handling the chain. A dull chain increases the risk of kickback.

Troubleshooting Guide

Parts List & Diagram

Key replacement parts for the McCulloch 250 include:

• Guide Bar (16", 20", etc.)
• Cutting Chain (.404" pitch, .063" gauge)
• Drive Sprocket (Rim or Spur type)
• Spark Plug (Champion CJ-7Y or equivalent)
• Air Filter
• Fuel Filter
• Starter Rope & Handle
• Clutch Assembly
• Carburetor Repair Kit

Note: Refer to the official McCulloch 250 Illustrated Parts List (IPL) for the complete diagram and part numbers. Always use genuine or high-quality replacement parts.

Support: For technical assistance or parts, contact a certified McCulloch service dealer or visit official parts suppliers online.