manual stihl ms 251

1.2 Target Audience and Use Cases

The Stihl MS 251 is designed for both professionals and homeowners needing a reliable chainsaw. It excels in logging, firewood cutting, and pruning.

• Suitable for medium-duty tasks requiring precision and power;
• Ideal for landscapers, farmers, and DIY enthusiasts.
• Perfect for cutting small to medium-sized trees and branches.

Its versatility makes it a go-to tool for various outdoor projects, ensuring efficient performance across different applications.

1.3 Importance of the Manual for Users

The manual is essential for safe and effective use of the Stihl MS 251. It provides detailed instructions for assembly, operation, and maintenance, ensuring users understand proper techniques.

• Guides users through safety precautions to prevent accidents.
• Explains troubleshooting steps for common issues like starting problems.
• Offers tips for optimal performance and longevity of the chainsaw.
• Helps users understand proper chain tensioning and lubrication.

By following the manual, users can maximize efficiency, reduce wear, and ensure reliable operation of their Stihl MS 251 chainsaw.

Safety Precautions and Working Techniques

Always follow proper starting procedures to avoid flooding the engine. Adhere to safety guidelines in the manual to prevent accidents and ensure efficient operation of the chainsaw.

2.1 General Safety Guidelines

Always follow proper starting procedures to avoid engine flooding. Ensure the chainsaw is on a flat, stable surface before starting. Wear Personal Protective Equipment (PPE), including safety glasses, gloves, and sturdy footwear. Keep loose clothing tied back and avoid jewelry that could catch; Maintain a firm grip and proper stance for control. Never operate the saw near open flames or sparks. Regularly inspect the chain for sharpness and damage. Keep bystanders at a safe distance. Follow all guidelines in the manual to prevent accidents and ensure efficient operation. Proper techniques and precautions are essential for safe and effective use of the Stihl MS 251.

2.2 Personal Protective Equipment (PPE)

Wearing proper Personal Protective Equipment (PPE) is crucial when operating the Stihl MS 251. This includes safety glasses, ear protection, gloves, and sturdy footwear. A helmet with a face shield is recommended to protect against flying debris. Ensure all clothing is tight-fitting and free from loose ends that could catch. Steel-toe boots or chainsaw-resistant footwear is essential to prevent foot injuries. Never operate without gloves, as they provide grip and protection. Proper PPE significantly reduces the risk of injury from debris or accidental chain contact. Always prioritize safety by wearing the recommended gear before starting the chainsaw.

2.3 Emergency Procedures and First Aid

In case of an emergency, turn off the chainsaw immediately and remain calm. If injured, seek medical attention promptly. For cuts or lacerations, apply direct pressure to control bleeding.

• Remove any embedded debris carefully without rubbing the wound.
• Clean the injury with sterile water and cover it with a clean bandage.
• For burns, cool the area with clean water and avoid direct contact.

Prevent further accidents by addressing the cause of the incident. Regular maintenance can help avoid malfunctions. Always keep a first aid kit nearby when operating the chainsaw.

Technical Specifications of the Stihl MS 251

The Stihl MS 251 features a powerful engine, adjustable bar and chain lengths, and a lightweight design for enhanced ergonomics. It requires specific fuel and oil ratios for optimal performance.

3.1 Engine Power and Performance

The Stihl MS 251 is equipped with a robust 2-stroke engine, delivering reliable power for demanding cutting tasks. With an approximate 50cc displacement, it offers high torque and efficient fuel consumption.

• Engine power is optimized for heavy-duty applications.
• Cylinder capacity ensures smooth operation and reduced emissions.
• The 2-stroke design provides quick acceleration and responsiveness.
• Manual guidelines emphasize proper fuel-to-oil ratios for peak performance.

This engine setup makes the MS 251 ideal for professionals and homeowners needing consistent power and durability.

3.2 Bar and Chain Length Options

The Stihl MS 251 offers flexibility with various bar and chain configurations. It supports bar lengths from 16 to 20 inches, catering to different cutting needs.

• 16-inch bar ideal for smaller logs and precise cuts;
• 20-inch bar suitable for larger trees and heavy-duty tasks.
• Chain options include PMM3 and PMX types for efficiency and durability.
• Proper bar and chain pairing ensures optimal performance and safety.

The manual provides guidance on selecting the right combination for specific tasks, ensuring users achieve maximum productivity and tool longevity.

3.3 Weight and Ergonomic Design

The Stihl MS 251 weighs approximately 10.6 lbs, making it lightweight and maneuverable for extended use. Its ergonomic design focuses on comfort and control, featuring a well-balanced layout.

• Soft-grip handle reduces vibration and fatigue.
• Anti-vibration system minimizes strain during operation.
• Compact design allows easy handling in tight spaces.
• Weight distribution enhances stability and precision cutting.

These ergonomic features ensure users can work efficiently with reduced physical strain, making the MS 251 suitable for both professionals and casual users.

3.4 Fuel and Oil Requirements

The Stihl MS 251 requires a precise fuel-oil mixture of 50:1, using high-quality unleaded gasoline and STIHL HP Ultra oil. Proper lubrication ensures engine longevity and optimal performance.

• Always use the correct ratio to avoid engine damage.
• Regularly check and clean the air filter to maintain proper combustion.
• Use fresh fuel to prevent clogging and performance issues.
• Drain old fuel if the saw will be stored for extended periods.

Following these guidelines ensures reliable operation and minimizes maintenance needs, keeping the chainsaw running smoothly for years.

Assembly and Initial Setup

Unbox and inventory all parts, then mount the guide bar and chain. Adjust the chain tension and test the saw to ensure proper function before use.

4.1 Unboxing and Inventory of Parts

When unboxing the Stihl MS 251, carefully inspect all components for damage. Ensure the package includes the chainsaw, guide bar, chain, screwdriver, wrench, and manual.

• Verify the guide bar and chain are correctly matched to the saw.
• Check for any signs of shipping damage or missing items.
• Familiarize yourself with the tools provided for assembly and adjustments.

Organize the parts and tools to ensure a smooth setup process. Refer to the manual for a detailed inventory list and instructions.

4.2 Mounting the Guide Bar and Chain

Mounting the guide bar and chain on the Stihl MS 251 requires precision to ensure proper function. Start by aligning the guide bar with the saw’s mounting bracket, ensuring it fits securely.

• Tighten the bar nuts evenly to avoid misalignment.
• Install the chain, ensuring the correct orientation as marked by the arrows.
• Use the provided wrench to secure the chain tensioner.
• Refer to the manual for specific torque specifications.

Double-check the chain tension and alignment before testing the saw. Proper installation ensures safe and efficient cutting performance.

4.3 Adjusting the Chain Tension

Proper chain tension is crucial for safe and efficient operation of the Stihl MS 251. Start by locating the chain tensioning screw on the side of the saw.

• Use a screwdriver to turn the tensioning screw clockwise to tighten or counterclockwise to loosen the chain.
• Check the tension by pulling the chain midway between the bar and the saw; it should have minimal slack but not be overly tight.
• Ensure the chain is properly aligned with the guide bar to prevent uneven wear.
• After adjusting, test the saw to confirm the chain runs smoothly and does not bind.

Incorrect tension can lead to poor performance or damage, so always refer to the manual for specific guidelines.

4.4 Initial Settings and Testing

After assembling the Stihl MS 251, perform initial settings and testing to ensure proper function. Start by checking all controls, such as the chain brake and throttle, for smooth operation.

• Test the chain brake by engaging and disengaging it to confirm it stops the chain instantly.
• Check the chain tension and adjust if necessary to ensure it runs smoothly without binding.
• Perform a cold start to verify the engine runs steadily and the chain rotates correctly.
• Make small cuts to test the saw’s performance and adjust settings as needed.

Proper initial testing ensures safety and optimal performance for your first cutting tasks.

Operating the Stihl MS 251

Start with a cold engine, using full choke for initial ignition. Once running, switch to half choke and adjust as needed for smooth operation.

• Engage the chain brake before starting to ensure safety.
• Use proper cutting techniques, maintaining control and balance.
• Shut down by idling the engine and disengaging the chain.

Always follow manual guidelines for efficient and safe operation.

5.1 Starting the Chainsaw (Cold and Warm Start)

Starting the Stihl MS 251 requires careful steps to ensure reliable ignition. For a cold start, pull the choke fully and engage the chain brake. Pull the starter rope no more than five times. If it doesn’t start, switch to half choke and continue pulling until it ignites. For a warm start, the process is simpler, as the engine is already primed. Always engage the chain brake before starting to prevent accidental chain movement. If the saw doesn’t start after several attempts, check for flooding by removing the spark plug and smelling the threads for gas. Proper starting techniques prevent engine flooding and ensure smooth operation.

5.2 Basic Cutting Techniques

Mastering basic cutting techniques with the Stihl MS 251 ensures safe and efficient operation. Start by maintaining a firm, balanced stance with both hands on the saw. Grip the handle firmly, with your thumb under the guard for control. For felling trees, make a horizontal cut one-third of the trunk’s diameter from the side you want it to fall. Follow with a vertical cut from the opposite side, leaving a hinge. For bucking, use a “topping” or “snip” cut, keeping the chain moving smoothly. Always cut on the pull stroke, using the weight of the saw. Regularly sharpen the chain and maintain proper angle to avoid kickback. Practice these techniques to improve precision and safety.

5.3 Shutting Down the Chainsaw

To safely shut down the Stihl MS 251, ensure the chain comes to a complete stop before turning off the engine. Move to a safe area away from flammable materials or bystanders. Release the throttle and allow the engine to idle for a few seconds to cool down. Avoid sudden stops, as this can damage the engine. Turn off the ignition and engage the chain brake. Regularly check and maintain the chain and bar to prevent wear. Store the saw in a dry, secure location, following proper winterization steps if necessary. Always refer to the manual for specific storage and maintenance guidelines.

Maintenance and Servicing

Regular maintenance is crucial for the Stihl MS 251. Daily checks, cleaning, and lubrication ensure optimal performance. Follow the manual’s guidelines for servicing and storage to maximize longevity.