Stihl provides a comprehensive instruction manual for the MS 251‚ crucial for safe and effective operation. Understanding this manual ensures proper use and longevity.
Overview of the Stihl MS 251
The Stihl MS 251 is a widely-used gasoline-powered chainsaw‚ known for its balance of power and maneuverability‚ making it suitable for various cutting tasks. The instruction manual serves as a vital resource‚ detailing everything from initial setup to detailed maintenance procedures. It emphasizes safety‚ guiding users through proper operation to prevent accidents.
This manual isn’t just a set of directions; it’s a comprehensive guide to understanding the machine itself. It covers the chainsaw’s components‚ their functions‚ and how to maintain them for optimal performance. Referencing the manual before each use is strongly advised‚ ensuring users are familiar with all safety warnings and operational guidelines.
Key Features and Specifications
The Stihl MS 251’s manual highlights key features like its 2-stroke engine‚ delivering a balance of power and fuel efficiency. Specifications detailed within include engine displacement‚ power output‚ and bar length options. The manual stresses the importance of using the correct fuel mix ratio for optimal engine performance and longevity.
Furthermore‚ the instruction manual outlines safety features such as the chain brake‚ anti-vibration system‚ and throttle lockout. Detailed diagrams and explanations clarify these features’ functions. Understanding these specifications‚ as presented in the manual‚ is crucial for safe and effective operation‚ ensuring the chainsaw performs as intended and remains reliable.
Understanding the Manual
The STIHL instruction manual is essential for safe operation of the MS 251 chainsaw; carefully read and follow all provided instructions.
Importance of Reading the Manual
Reading the Stihl MS 251 manual before operation is paramount for safety and machine longevity. The manual details critical safety precautions‚ preventing potential injuries from this powerful tool. It outlines proper operating procedures‚ ensuring efficient cutting and minimizing wear and tear. Ignoring the instructions can lead to damage‚ void warranties‚ and‚ most importantly‚ serious harm.
The manual isn’t just a list of rules; it’s a guide to understanding your chainsaw. It explains each component’s function and how they interact‚ empowering you to perform basic maintenance and troubleshooting. Contacting your STIHL dealer is advised if any instruction remains unclear‚ prioritizing a safe and informed user experience. Thorough comprehension is key to responsible chainsaw use.
Guide to Using this Manual
This Instruction Manual serves as a comprehensive guide for your STIHL chain saw‚ the MS 251. It refers to the machine throughout‚ offering detailed explanations of its operation and maintenance. Before each use‚ review the safety precautions and operating procedures. Pay close attention to warnings‚ indicated clearly within the text‚ to prevent accidents and ensure safe handling.
The manual is structured logically‚ covering assembly‚ operation‚ maintenance‚ and troubleshooting. Familiarize yourself with the layout to quickly locate relevant information. If any instruction is unclear‚ consult your STIHL dealer or distributor for clarification. Remember‚ understanding this manual is crucial for maximizing the performance and lifespan of your MS 251.
Safety Precautions
WARNING: Because a chain saw presents inherent risks‚ carefully read and understand all safety precautions detailed in this manual before operating the STIHL MS 251. Always wear appropriate personal protective equipment‚ including safety glasses‚ hearing protection‚ gloves‚ and sturdy footwear. Ensure a firm grip and maintain a safe distance from the chain.
Never operate the chainsaw with a damaged chain or dull blade. Be aware of your surroundings and potential hazards like overhead obstructions or uneven terrain. Always engage the chain brake when not actively cutting. Improper use can lead to serious injury. Contact your STIHL dealer if you have any questions regarding safe operation.
Assembly and Initial Setup
The manual guides unpacking‚ inspection‚ chain installation‚ and proper tensioning of the STIHL MS 251. Correct setup is vital for safe operation.
Unpacking and Inspection
Stihl’s manual emphasizes a thorough unpacking and inspection process immediately upon receiving your MS 251 chainsaw. Carefully remove all components from the packaging‚ verifying that everything listed in the manual is present. Inspect the chainsaw itself for any visible damage incurred during shipping – look for cracks‚ dents‚ or loose parts.
Pay close attention to the guide bar‚ chain‚ and protective covers. Ensure the chain is securely attached (though initial tensioning comes later) and the guide bar isn’t bent. The manual stresses reporting any damage to your STIHL dealer immediately. Retain the packaging materials for potential return or warranty claims‚ as instructed within the manual; A complete inspection ensures safe and efficient operation from the start.
Chain Installation and Tensioning
The Stihl MS 251 manual provides detailed instructions for correct chain installation. Ensure the chainsaw is switched off and the spark plug disconnected before beginning; Properly orient the chain around the bar‚ matching the cutting edges to the correct direction. The manual illustrates this clearly.
Tensioning is critical; the chain should fit snugly against the bar but move freely by hand. Adjust tension using the tensioning screw‚ as depicted in the manual. A properly tensioned chain prevents derailment and ensures efficient cutting. Regularly check and readjust tension‚ especially during initial use‚ following the manual’s guidance. Incorrect tension can damage the bar‚ chain‚ and chainsaw.
Fueling and Oil Mixing
The Stihl MS 251 manual emphasizes the importance of using the correct fuel mixture. Always use a high-quality‚ unleaded gasoline mixed with STIHL 2-stroke engine oil. The recommended ratio is clearly stated within the manual – typically 50:1‚ but verify this!
Proper mixing ensures optimal engine performance and longevity. The manual details the correct procedure for mixing‚ stressing the need for thorough blending. Use a dedicated fuel container and always add oil before gasoline. Also‚ the manual highlights the necessity of using fresh fuel and avoiding prolonged storage. Incorrect fuel mixtures can cause engine damage and void the warranty.
Operation of the Stihl MS 251
The manual details starting procedures‚ proper cutting techniques‚ and the critical function of the chain brake for safe STIHL MS 251 operation.
Starting the Chainsaw
The STIHL MS 251 manual emphasizes a specific starting procedure for optimal performance and safety. Before attempting to start‚ ensure the chainsaw is placed on a firm‚ level surface‚ clear of obstructions. Always engage the chain brake. Confirm the air filter is clean and the spark plug is in good working order‚ as detailed within the manual.
Follow the prescribed sequence: activate the choke‚ set the throttle to the starting position‚ and firmly grasp the front handle with one hand and the rear handle with the other. Pull the starter cord with a smooth‚ deliberate motion. Once the engine sputters‚ disengage the choke and continue pulling until the engine starts. Refer to the manual’s illustrations for clarity.
Proper Cutting Techniques
The STIHL MS 251 manual stresses safe and efficient cutting practices. Always maintain a firm grip with both hands‚ keeping a secure stance. Avoid cutting above shoulder height‚ and be mindful of kickback – a dangerous reaction described in detail within the manual; Utilize the correct cutting technique for the type of wood and cut being made‚ such as bucking or felling.
Plan your cuts carefully‚ ensuring no obstructions hinder your movement or the chainsaw’s operation. Never force the saw; let the chain do the work. Regularly inspect the wood for hidden nails or other foreign objects. The manual provides diagrams illustrating proper body positioning and cutting angles for various scenarios‚ promoting operator safety and control.
Chain Brake Functionality
The STIHL MS 251 manual emphasizes the critical importance of the chain brake. This safety feature instantly stops the chain rotation‚ minimizing injury during kickback or emergencies. The manual details how to engage the brake manually and explains its automatic activation during kickback events. Regular inspection and testing of the chain brake are vital for ensuring its proper function.
Understanding the chain brake’s operation‚ as outlined in the manual‚ is paramount for safe chainsaw use. It’s crucial to know how to disengage the brake for starting and operation‚ and re-engage it immediately after use or before transport. The manual provides clear instructions and diagrams illustrating the brake’s components and testing procedures.
Maintenance and Servicing
The STIHL MS 251 manual details essential maintenance‚ including cleaning‚ sharpening‚ and filter replacements‚ to ensure optimal performance and longevity of the chainsaw.
Cleaning and Inspection
Stihl MS 251’s manual emphasizes regular cleaning to prevent build-up of sawdust and debris‚ crucial for efficient operation and preventing damage. After each use‚ thoroughly clean the chainsaw housing‚ paying close attention to cooling fins and air intake areas. Inspect the chain for sharpness and damage‚ and the bar for wear.
The manual advises checking all nuts‚ bolts‚ and screws for tightness before each use‚ ensuring safe operation. Regularly inspect the anti-vibration system for wear and tear. A visual inspection of the fuel and oil tanks for leaks or damage is also recommended. Consistent cleaning and inspection‚ as outlined in the manual‚ significantly extend the chainsaw’s lifespan and maintain its performance.
Chain Sharpening
The Stihl MS 251 manual details the importance of a sharp chain for efficient and safe cutting. A dull chain requires more force‚ increasing kickback risk and reducing performance. The manual recommends using a round file of the correct size‚ guided by a sharpening gauge to maintain the correct depth gauges and angles.
Proper sharpening involves filing each cutter tooth to the specified length and angle‚ ensuring consistent cutting performance. The manual stresses the importance of maintaining consistent filing pressure and stroke length. After sharpening‚ it’s crucial to check the depth gauges and file them down if necessary. Regular chain sharpening‚ following the manual’s guidance‚ maximizes cutting efficiency and minimizes user fatigue.
Bar Maintenance
The Stihl MS 251 manual emphasizes regular bar maintenance for optimal chainsaw performance and longevity. This includes cleaning the bar groove to remove accumulated sawdust and debris‚ preventing binding and ensuring smooth chain travel. The manual advises inspecting the bar rails for wear and burrs‚ which can cause increased chain friction and damage.
Periodically‚ the bar should be flipped to distribute wear evenly. The manual details how to check bar straightness and recommends replacing the bar if it becomes bent or severely worn. Proper lubrication is also critical; the manual stresses maintaining adequate oil levels and ensuring the oiler is functioning correctly. Consistent bar maintenance‚ as outlined in the manual‚ extends the life of both the bar and chain.
Air Filter Cleaning and Replacement
The Stihl MS 251 manual details the importance of a clean air filter for engine performance and longevity. A dirty filter restricts airflow‚ leading to reduced power and increased fuel consumption. The manual instructs users to regularly check and clean the filter‚ typically after every 5 operating hours or more frequently in dusty conditions.
Cleaning involves removing the filter and brushing away debris‚ or washing it with mild soap and water. The manual specifies drying the filter completely before reinstallation. It also outlines the procedure for replacing the air filter when it becomes damaged or excessively dirty. Following the manual’s guidance ensures optimal engine operation and prevents premature wear.
Spark Plug Maintenance
The Stihl MS 251 manual emphasizes regular spark plug maintenance for reliable engine starting and efficient combustion. The manual instructs users to inspect the spark plug periodically for fouling‚ wear‚ or damage. A properly functioning spark plug is vital for optimal engine performance.
Cleaning the spark plug involves removing carbon buildup with a wire brush‚ ensuring the correct gap is maintained as specified in the manual. The manual details the correct torque specification for tightening the spark plug. Replacement is recommended annually or when the plug exhibits significant wear. Adhering to these guidelines‚ as outlined in the manual‚ ensures consistent ignition and prevents engine misfires.
Fuel Filter Replacement
The Stihl MS 251 manual details the importance of a clean fuel filter for consistent engine operation. A clogged filter restricts fuel flow‚ leading to performance issues. The manual recommends periodic replacement‚ typically annually or more frequently with heavy use. Locate the fuel filter within the fuel tank‚ as illustrated in the manual.
To replace‚ carefully remove the old filter and install a new one‚ ensuring a proper seal to prevent fuel leaks. The manual provides clear diagrams for this process. Always use a genuine Stihl replacement filter to maintain optimal performance and avoid damage. Following the manual’s instructions guarantees a clean fuel supply and extends engine life.
Servicing Aids (Grease and Sealant)
The Stihl MS 251 manual emphasizes the use of specific Stihl servicing aids – specialized grease and sealant – for optimal maintenance. These aren’t generic replacements; they’re formulated for the chainsaw’s components. The manual details where to apply Stihl grease‚ such as on the sprocket and guide bar rails‚ reducing friction and wear.
Stihl sealant is crucial for preventing oil leaks from the engine casing and maintaining proper lubrication. The manual illustrates application points and quantities. Using the correct aids‚ as described in the manual‚ ensures long-term reliability and prevents premature failure of critical parts. Always refer to the manual for specific product recommendations.
Troubleshooting Common Issues
The Stihl MS 251 manual provides guidance for resolving typical problems like starting failures‚ rough running‚ or excessive vibration‚ ensuring continued operation.
Chainsaw Won’t Start
If your Stihl MS 251 fails to start‚ the manual directs you to systematically check several key components. First‚ verify the fuel tank contains a fresh fuel mix‚ adhering to the specified ratio.
Next‚ inspect the spark plug for fouling or damage‚ cleaning or replacing it as needed. Ensure the spark plug connector is securely attached. The manual also emphasizes checking the air filter for obstructions‚ as a clogged filter restricts airflow.
Confirm the chain brake is disengaged. Finally‚ examine the fuel lines for kinks or blockages. Following these steps‚ detailed within the instruction manual‚ will often resolve starting issues. Contact a STIHL dealer if problems persist.
Chain Runs Roughly
A roughly running chain on your Stihl MS 251‚ as detailed in the manual‚ often indicates issues with chain tension or sharpness. First‚ verify the chain tension is correct; a loose chain will vibrate and run unevenly. Refer to the manual’s illustrations for proper adjustment.
Next‚ inspect the chain for dullness. A dull chain requires significantly more force and results in a jerky operation. Sharpen the chain according to the manual’s guidelines‚ maintaining the correct filing angle.
Also‚ check the bar for damage or wear‚ and ensure it’s properly lubricated. A damaged bar or insufficient lubrication can contribute to rough chain operation. Consistent maintenance‚ as outlined in the instruction manual‚ is key.
Excessive Vibration
The Stihl MS 251 manual addresses excessive vibration‚ a common concern. Significant vibration often signals a problem with the anti-vibration system. Inspect the rubber mounts connecting the engine and handles – damage requires professional repair. Ensure all screws and bolts are tightened to the specifications detailed in the instruction manual.
A dull or damaged chain can also amplify vibration. Sharpen or replace the chain as needed‚ following the manual’s guidance. Improper chain tension contributes to vibration; adjust it correctly.
Finally‚ verify the bar is correctly installed and undamaged. Consistent‚ preventative maintenance‚ as described in the manual‚ minimizes vibration and extends the chainsaw’s lifespan.
Technical Specifications
The Stihl MS 251 manual details precise specifications‚ including engine displacement‚ fuel capacity‚ and weight‚ aiding in informed operation and maintenance.
Detailed Specifications of MS 251
The Stihl MS 251’s manual meticulously outlines its technical details. Engine displacement is 45.4 cc (2.77 cu. in.)‚ powered by a 2-stroke engine. Fuel capacity reaches 250 ml (8.5 oz)‚ while the oil tank holds 260 ml (8.8 oz).
Dry weight‚ excluding bar and chain‚ is approximately 5.8 kg (12.8 lbs). The chain pitch options are 3/8” P‚ and the bar lengths vary‚ commonly ranging from 30cm (12”) to 45cm (18”). The manual also specifies sound power level at 105 dB(A) and vibration levels‚ crucial for operator safety.
Furthermore‚ it details the carburetor type and ignition system specifics‚ providing a complete technical profile for servicing and understanding the chainsaw’s performance characteristics‚ all found within the comprehensive manual.
Compatibility with Accessories
The Stihl MS 251 manual details a range of compatible accessories to enhance functionality. These include various guide bars‚ differing in length and sprocket nose configurations‚ optimizing cutting for diverse tasks; Stihl offers a selection of chains‚ matched to bar lengths and cutting needs‚ detailed within the manual.
Additional compatible accessories encompass carrying cases for safe transport‚ sharpening kits for maintaining chain performance‚ and specialized tools for assembly and maintenance. The manual also references appropriate safety gear‚ like protective chaps and helmets‚ crucial for operator wellbeing.
Furthermore‚ it notes compatibility with Stihl’s 2-stroke oil and fuel mixtures‚ ensuring optimal engine performance and longevity. Referencing the manual guarantees correct accessory selection and safe operation.