The STIHL MS 251 is a robust and efficient mid-range chainsaw designed for homeowners and professionals, offering reliability and versatility for cutting firewood and felling small trees․
Safety Precautions and Working Techniques
The STIHL MS 251 requires strict adherence to safety protocols․ Always wear protective gear, engage the chain brake during transport, and ensure proper handling techniques to minimize accident risks․
General Safety Tips
Operating the STIHL MS 251 requires careful attention to safety․ Always wear protective clothing, including steel-toed boots, safety glasses, and hearing protection․ Ensure the chain brake is engaged during transport and when the saw is not in use․ Avoid operating the saw in poor weather conditions or under the influence of substances that impair judgment․ Keep bystanders, especially children and pets, at a safe distance․ Never modify the saw or use unauthorized attachments, as this can increase the risk of injury․ Regularly inspect the machine for damage or wear and ensure all parts are properly assembled․ Follow all local safety regulations and guidelines․ If inexperienced, seek training or guidance from a qualified user or professional․ Always prioritize caution to prevent accidents and ensure safe operation․
Protective Clothing and Equipment
Wearing proper protective clothing and equipment is essential when operating the STIHL MS 251 chainsaw․ This includes a safety helmet, safety glasses, or a face shield to protect against debris․ Hearing protection, such as earplugs or earmuffs, is also required to prevent noise-induced hearing damage․ Gloves provide a secure grip and protect hands from cuts and abrasions․ Steel-toed boots with cut-retardant inserts are recommended to safeguard feet from injury․ Clothing should be snug-fitting and free from loose ends that could catch on branches or moving parts․ STIHL offers a comprehensive range of personal protective equipment designed to ensure safety and comfort during operation․ Always prioritize proper gear to minimize the risk of injury while using the chainsaw․
Fueling and Lubrication
The STIHL MS 251 requires a 50:1 fuel-to-oil mixture and features a 0․39-liter tank․ Regular chain lubrication ensures optimal performance and longevity of the cutting system․
Fueling Procedures
The STIHL MS 251 chainsaw requires a 50:1 fuel-to-oil mixture, using high-quality, unleaded gasoline with a minimum octane rating of 89․ Before refueling, ensure the engine is turned off and allowed to cool slightly․ Always fuel in a well-ventilated area, away from open flames or sparks․ Open the fuel cap slowly to release any pressure in the tank․ Use the supplied fuel cap, either screw-type or bayonet-type, and ensure it is securely tightened after refueling․ Check for any fuel leaks before starting the engine․ Never smoke or allow ignition sources near the saw during fueling․ If fuel spills, wipe it off immediately and change contaminated clothing․ Proper fueling ensures reliable performance and prevents damage to the engine․ Always refer to the instruction manual for specific guidelines․
Chain Lubrication
Proper chain lubrication is essential for the STIHL MS 251 chainsaw to ensure optimal performance and longevity․ The saw features an automatic oiler that continuously lubricates the bar and chain during operation․ Use high-quality STIHL chain oil, which is specifically designed to reduce wear and prevent overheating․ Check the chain oil tank regularly and refill as needed to maintain the recommended oil level․ Always use the correct viscosity oil for varying weather conditions, as specified in the instruction manual․ Insufficient lubrication can lead to premature chain wear and potential damage to the guide bar․ Monitor the oil flow during operation and clean the oil reservoir periodically to ensure smooth functionality․ Proper chain lubrication is critical for maintaining cutting efficiency and extending the life of your chainsaw․ Regular checks and maintenance will ensure reliable performance․
Chain Maintenance
Regular chain maintenance is crucial for the STIHL MS 251 to ensure optimal performance․ Clean the chain frequently to remove dirt and debris, and store it properly when not in use․ Always check for wear and damage, addressing issues promptly to maintain cutting efficiency and extend service life․ Proper care ensures reliable operation and longevity of the saw chain․
Tensioning the Saw Chain
Proper chain tension is essential for safe and efficient operation of the STIHL MS 251․ Check the chain tension regularly and adjust as needed to avoid poor cutting performance or increased wear․ To tension the chain, use the side chain tensioner or the quick chain tensioner, depending on your model․ Loosen the bar nuts slightly to allow movement, then tighten the tensioner until the chain sits snugly against the guide bar․ Ensure the chain does not sag excessively but still allows for slight movement when pulled gently․ After tensioning, retighten the bar nuts securely․ Proper tension prevents the chain from slipping or binding, ensuring smooth operation and extending the life of both the chain and guide bar․ Regular checks and adjustments are crucial for optimal performance․
Sharpening the Saw Chain
Sharpening the saw chain is crucial for maintaining cutting efficiency and safety․ The STIHL MS 251 chain should be sharpened when it no longer cuts cleanly or produces sawdust․ Use a high-quality filing kit specifically designed for chain saws․ Start by securing the chainsaw and engaging the chain brake․ File each cutter at the recommended angle (typically 30° to 35° for standard chains) using smooth, even strokes․ Ensure uniformity across all cutters to maintain balanced performance․ After sharpening, check and file the rakers if necessary to maintain the correct depth gauge setting․ Proper sharpening extends the chain’s life and ensures optimal cutting performance․ Always use STIHL-approved tools and follow the instructions in the manual for best results․ Regular maintenance ensures reliable operation and reduces wear on the saw․
Starting and Stopping the Engine
Starting the STIHL MS 251 chainsaw requires careful preparation․ Ensure the chain brake is engaged and the saw is on firm ground․ Move the master control lever to the “start” position․ Pull the starter rope gently until resistance is felt, then pull sharply․ Allow the rope to return fully before pulling again․ Once the engine coughs, move the lever to the “run” position․ For stopping, engage the chain brake and activate the stop switch․ Allow the engine to cool before storing or transporting the saw․ Always ensure the chain is stationary and the area is clear before starting or stopping the engine․ Proper starting and stopping techniques ensure safe operation and extend the saw’s lifespan․ Follow the manual’s guidelines for optimal performance․
Specifications of the STIHL MS 251
The STIHL MS 251 is a powerful and efficient chainsaw featuring a 45․6 cc, 2-stroke engine that delivers up to 3․0 horsepower․ With a maximum RPM of 10,000 and an idle speed of 2,800 RPM, it ensures smooth cutting performance․ The fuel tank capacity is 0․39 liters, allowing extended use without frequent refueling․ Weighing approximately 10․6 pounds (4․8 kg), it is designed for ease of handling․ The saw supports bar lengths from 16 to 20 inches, making it versatile for various cutting tasks․ Equipped with a side chain tensioner and quick chain tensioner, it offers convenient chain adjustment․ The STIHL MS 251 is built for reliability and durability, making it suitable for both professional and occasional use․ Its specifications ensure high performance and efficiency in demanding conditions․
Troubleshooting Common Issues
The STIHL MS 251 is a reliable chainsaw, but like any machine, it may encounter issues․ Common problems include the chain brake not engaging, poor engine performance, or excessive chain oil leakage․ If the chain brake fails to activate, ensure it is clean and free from debris․ For engine issues, check the fuel mixture, air filter, and spark plug․ Excessive oil leakage may indicate overfilling the chain oil tank or a damaged oil pump․ Starting difficulties can be resolved by ensuring the chain is properly tensioned and the muffler is clean․ Regular maintenance, such as sharpening the chain and cleaning the filter, can prevent many of these issues․ Always refer to the STIHL MS 251 manual for detailed troubleshooting guidance․
Winter Operation Tips
For optimal performance of the STIHL MS 251 in cold weather, ensure the machine is properly prepared․ Adjust the intake air baffle to the winter position to improve engine operation in low temperatures․ Always start the engine in a sheltered area and allow it to warm up before use․ Use a fuel mixture suitable for cold conditions, as specified in the manual․ Keep the fuel tank full to minimize condensation․ Regularly check chain tension and lubrication, as cold weather can affect these factors․ Clear snow from the machine before operation and store it in a dry place after use․ Dress warmly and work slowly to maintain control and safety during winter cutting tasks․
Storage and Maintenance
Proper storage and maintenance are crucial for extending the life of the STIHL MS 251․ Store the chainsaw in a dry, well-ventilated area away from direct sunlight․ Before storage, clean the machine thoroughly, removing dirt, oil, and debris․ Dry all metal parts to prevent rust․ Empty the fuel tank or use a fuel stabilizer if the saw will not be used for an extended period․ Tension the chain slightly to prevent it from sagging․ Regularly inspect the air filter, spark plug, and chain sprocket, replacing them as needed․ Always use the chain scabbard to protect the bar and chain during storage․ For long-term storage, follow the maintenance procedures outlined in the manual to ensure the saw remains in optimal condition․
Environmental Considerations and Emissions
The STIHL MS 251 is designed with environmental considerations in mind, featuring a powerful yet efficient 45․6 cc engine that minimizes fuel consumption and emissions․ The saw complies with emissions standards, ensuring reduced impact on the environment․ Regular maintenance, such as cleaning the air filter and spark plug, helps optimize performance and lower emissions․ Proper fueling techniques, like using a fuel stabilizer and avoiding spills, further reduce environmental impact․ Always use the recommended fuel-oil mixture to ensure efficient combustion and minimize exhaust emissions․ Additionally, STIHL recommends responsible disposal of waste materials and adherence to local regulations․ By following the manual guidelines, users can help maintain a cleaner environment while operating the MS 251․
Special Accessories and Parts
The STIHL MS 251 can be enhanced with a range of special accessories and parts designed to optimize performance and versatility․ These include high-quality guide bars, saw chains, and chain sprockets, all engineered to meet specific cutting needs․ STIHL offers original parts, such as the STIHL Oilomatic saw chain, which provides exceptional cutting efficiency and durability․ Additional accessories like the STIHL Quick Chain Tensioner simplify chain tensioning, while the STIHL Chain Scabbard protects the chain during transport․ For improved lubrication, STIHL recommends using STIHL Chain & Bar Lube․ These accessories ensure the saw operates at peak performance while maintaining reliability and safety․ Always use STIHL-approved parts to guarantee compatibility and maintain the warranty․ Consult the manual or a STIHL dealer for a full list of compatible accessories․