manual stihl ms 251
The STIHL MS 251 manual is a comprehensive guide designed to help users understand and operate their chainsaw safely and effectively. It covers safety precautions, operational procedures, and maintenance tips, ensuring both professionals and occasional users can maximize the tool’s potential while minimizing risks.
1.1 Purpose and Structure of the Manual
This manual provides essential guidance for the safe and effective operation of the STIHL MS 251 chainsaw. It is structured to help users understand the product’s features, safety precautions, and maintenance requirements. The manual is divided into clear sections, including technical specifications, operating instructions, and troubleshooting tips. Each section is designed to ensure users can maximize the chainsaw’s performance while adhering to safety standards. By following this guide, both professionals and occasional users can master the STIHL MS 251 with confidence and precision.
1.2 Important Safety Information
The STIHL MS 251 manual emphasizes critical safety measures to prevent accidents. Users must wear protective gear, including gloves, safety glasses, and hearing protection. Proper handling techniques are essential to avoid kickback, a common hazard. The manual also highlights the importance of maintaining the chainsaw, ensuring all components function correctly. Adhering to these guidelines ensures safe operation and minimizes risks associated with chainsaw use. Always refer to the manual for specific safety recommendations tailored to the MS 251 model.
Technical Specifications of the STIHL MS 251
The STIHL MS 251 features a 0.39-liter fuel tank, 10,000 RPM max speed, 2800 RPM idle, 450mm bar length, and 1/308″ chain pitch, powered by a two-stroke engine.
2.1 Engine Overview
The STIHL MS 251 is equipped with a powerful two-stroke, single-cylinder engine, featuring electronic magneto ignition for reliable starts. The engine utilizes a diaphragm carburetor, ensuring optimal air-fuel mixture delivery. Designed for high efficiency, the engine provides robust power while maintaining a compact and lightweight structure. Regular servicing, as outlined in the manual, is essential to maintain performance and longevity. Always refer to the manual for specific engine care and adjustment guidelines to ensure optimal operation.
2.2 Fuel System and Tank Capacity
The STIHL MS 251 features a fuel system with a diaphragm carburetor, designed for efficient fuel delivery. The saw has a fuel tank capacity of 0.39 liters, allowing for extended cutting sessions without frequent refueling. Proper fuel mixture, as specified in the manual, is essential for optimal performance. Always use high-quality gasoline mixed with STIHL HP Ultra oil at the recommended ratio. Regular inspection of the fuel system is crucial to prevent contamination and ensure reliability.
2.3 Chain and Bar Specifications
The STIHL MS 251 is equipped with a 16-inch (40 cm) guide bar, suitable for a wide range of cutting tasks. The saw chain features a 1/4″ pitch and 0.325″ gauge, ensuring efficient cutting performance. The chain is designed for durability and minimal kickback, enhancing safety. Proper chain tension and regular sharpening are essential for optimal performance. Always use STIHL-approved bars and chains to maintain reliability and safety, as specified in the manual.
Operating the STIHL MS 251
Operating the STIHL MS 251 requires attention to safety practices, proper starting procedures, and mastering cutting techniques. Always engage the chain brake before starting and maintain proper posture for control and stability during use.
3.1 Starting the Chainsaw
To start the STIHL MS 251, move to an open area and ensure the chain brake is engaged. Prime the fuel pump by pressing it several times until fuel flows into the priming chamber. Set the choke to the “start” position and pull the starter handle firmly until the engine coughs. Release the choke and pull the starter again until the engine runs. Allow the saw to warm up briefly before use. Always ensure the chain brake is engaged before starting to prevent accidental start-ups and ensure safety.
3.2 Basic Cutting Techniques
Always maintain proper stance and grip, with hands firmly on the handles and eyes on the cutting area. Ensure the chain is sharp and properly tensioned to prevent kickback. Start cuts with the chain running at full speed, using a steady, controlled motion. Make small, precise cuts to avoid overloading the saw. Plan your cutting path to minimize sawing through knots or twisted wood. Avoid cutting sideways or applying excessive pressure, as this can increase the risk of kickback. Use techniques like boring (cutting slowly and steadily) or snapping (quick cuts for smaller branches) to achieve clean, efficient results.
3.4 Chain Brake System
The chain brake system is a critical safety feature on the STIHL MS 251, designed to stop the saw chain instantly in emergency situations. It activates manually by pushing the brake forward, halting the chain within a fraction of a second. This system reduces the risk of injury, especially during kickback events. Always ensure the brake is functioning properly before use and test it periodically to maintain reliability. Proper use of the chain brake is essential for safe and controlled operation of the chainsaw.
Maintenance and Servicing
Regular maintenance ensures optimal performance and longevity of the STIHL MS 251. This section covers essential tasks such as air filter cleaning, carburetor adjustment, and chain maintenance. Refer to specific sections for detailed guidance on each procedure.
4.1 Air Filter Cleaning and Replacement
Regular cleaning and replacement of the air filter are crucial for maintaining the STIHL MS 251’s performance. The manual provides step-by-step guidance on how to remove, clean, and reinstall the air filter. It emphasizes the importance of using genuine STIHL parts to ensure proper fitment and functionality. Additionally, the manual outlines the recommended intervals for filter replacement to prevent engine damage and maintain optimal airflow. Always refer to the manual for precise instructions to avoid any potential issues during maintenance.
4.2 Carburetor Adjustment
The STIHL MS 251 manual provides detailed instructions for carburetor adjustment, ensuring optimal engine performance. Adjustments are made using the idle and high-speed screws, requiring a screwdriver. Proper tuning is essential for smooth operation and fuel efficiency. The manual warns against over-adjustment, which can lead to engine damage or poor performance. It is recommended to consult a STIHL dealer if unsure, as improper adjustments can void the warranty or pose safety risks. Always follow the manual’s specific guidelines for accurate settings.
4.3 Chain Maintenance and Sharpening
Regular chain maintenance is crucial for optimal performance of the STIHL MS 251. The manual emphasizes cleaning the chain and bar daily to prevent debris buildup. Sharpening the chain correctly is essential, using a 5.5mm file for standard chains. Proper technique ensures even cutter and tie strap alignment. Dull or improperly sharpened chains reduce efficiency and increase wear. Always follow the manual’s specific sharpening guide to maintain cutting performance and extend chain life. Improper sharpening can lead to premature wear or unsafe operation.
Safety Precautions and Reactive Forces
The manual highlights understanding reactive forces, proper protective gear, and safe handling techniques to ensure operator safety while using the STIHL MS 251 chainsaw effectively.
5.1 Understanding Reactive Forces
Understanding reactive forces is crucial for safe operation. These forces, including kickback and pushback, occur during cutting. Kickback happens when the chain’s upper part binds, causing the saw to jerk upward. Pushback occurs when the chain binds at the bottom, pushing the saw backward. The manual explains how to identify and mitigate these forces through proper technique, chain maintenance, and using the chain brake system effectively to ensure control and prevent accidents. Always maintain focus and proper stance to handle these forces safely.
5.2 Proper Protective Equipment
Proper protective equipment is essential for safe operation of the STIHL MS 251. Always wear a helmet with face protection, safety glasses, and hearing protection to guard against debris and noise. Durable gloves improve grip and control, while chainsaw chaps or sturdy pants protect legs from potential cuts. Steel-toed boots provide additional protection for feet. Ensure all gear fits properly and meets safety standards. This equipment minimizes injury risks and is crucial for both professionals and occasional users. Always prioritize wearing protective gear before starting the chainsaw.
Troubleshooting Common Issues
This section addresses common problems like engine not starting, chain malfunctions, and overheating. It provides diagnostic steps and solutions to restore optimal performance quickly and safely.
6.1 Engine Not Starting
If the engine fails to start, check the fuel system for proper mixture and sufficiency. Ensure the air filter is clean and the spark plug is functioning. Verify that the choke is correctly positioned and the carburetor is adjusted. If issues persist, inspect for fuel leaks or carburetor blockages. Consult the manual for detailed diagnostic steps to address ignition or fuel system problems effectively.
6.2 Chain Not Cutting Properly
If the chain is not cutting effectively, check its sharpness and tension. A dull chain or incorrect tension can significantly reduce cutting performance. Ensure the chain is properly sharpened or replaced if worn. Verify the bar alignment and clean any debris blocking the cutting area. Consult the manual for guidance on adjusting the chain tension and maintaining optimal cutting efficiency. Proper chain maintenance is essential for consistent performance and safety.
6.3 Overheating Issues
If the STIHL MS 251 overheats, check for blockages in the air filter or cooling system. Ensure proper airflow by cleaning or replacing the air filter. Verify that the chain is not too tight, as excessive tension can cause friction and heat buildup. Avoid cutting materials like metal or hard plastic, as they can overburden the engine. If overheating persists, consult the manual for guidance or contact a STIHL authorized service center to address potential internal issues.
Warranty and Support Information
STIHL provides comprehensive warranty coverage and dedicated support through its authorized dealer network. For inquiries or repairs, contact your local STIHL dealer or visit their official website for online resources and manuals.
7.1 STIHL Dealer Network
The STIHL dealer network provides comprehensive support for MS 251 owners. Authorized dealers offer expert advice, genuine parts, and professional repairs. They ensure your chainsaw operates at peak performance. Regular maintenance, warranty services, and troubleshooting are handled efficiently. Visit your local STIHL dealer for personalized assistance, ensuring your MS 251 remains reliable and safe to use. Dealers are trained to address specific needs, guaranteeing optimal performance and longevity of your machine.
7.2 Online Resources and Manuals
STIHL provides accessible online resources and manuals for the MS 251. Users can download PDF versions of the instruction manual, ensuring easy access to vital information. These resources cover safety guidelines, technical specifications, and maintenance tips. Additionally, troubleshooting guides and repair instructions are available, helping users resolve common issues independently. The official STIHL website offers a dedicated section for manuals, ensuring owners can always find the support they need to keep their MS 251 in optimal condition.