Stihl MS 251 Manual: A Comprehensive Guide
Welcome! This guide provides comprehensive information about the Stihl MS 251 chainsaw․ It covers everything from key features and safety precautions to maintenance, troubleshooting, and available resources․ You’ll find helpful diagrams and exploded views to assist with repairs․
The Stihl MS 251 WOOD BOSS chainsaw is engineered to deliver the robust power and reliable performance expected from Stihl equipment, combined with a user-friendly and ergonomic design․ This makes it an excellent choice for homeowners and occasional users tackling a variety of tasks around the yard or property․
Specifically, the MS 251 is well-suited for felling smaller trees, efficiently pruning and thinning branches, and easily cutting firewood for home heating or recreational use․ Its balanced design and anti-vibration system contribute to reduced operator fatigue, allowing for comfortable extended use․ The single-lever master control simplifies operation by integrating start, choke, throttle, and stop functions into one convenient control․
Furthermore, the MS 251 incorporates features like the Ematic chain lubrication system, ensuring proper chain lubrication for extended bar and chain life․ It also has tool-free fuel and oil caps, making refueling and oiling quick and easy․ This combination of power, ease of use, and convenient features makes the Stihl MS 251 a versatile and valuable tool for various cutting applications․
Key Features of the MS 251
The Stihl MS 251 chainsaw boasts several features designed to enhance performance, usability, and safety․ One notable feature is the Ematic chain lubrication system, which optimizes oil consumption and reduces wear on the bar and chain․ This system ensures proper lubrication, extending the life of these critical components and minimizing downtime for maintenance․
For user comfort, the MS 251 incorporates an anti-vibration system, effectively reducing vibrations transmitted to the operator’s hands and arms․ This feature minimizes fatigue during prolonged use, enhancing comfort and control․ The single-lever master control simplifies operation by integrating start, choke, throttle, and stop functions into a single, easily accessible lever․
The MS 251 also features tool-free filler caps for both fuel and oil tanks, allowing for quick and convenient refills without the need for additional tools․ This design streamlines the refueling process and reduces downtime․ The inclusion of a chain brake system provides an added layer of safety․ These features combine to make the MS 251 a powerful, user-friendly, and safe chainsaw for various cutting tasks․
Safety Precautions and Operation
Operating the Stihl MS 251 chainsaw safely requires strict adherence to safety precautions․ Before each use, thoroughly inspect the chainsaw for any damage or loose parts․ Ensure the chain is properly sharpened and tensioned, and the chain brake is functioning correctly․ Always wear appropriate personal protective equipment (PPE), including safety glasses, hearing protection, gloves, and sturdy footwear․
When starting the chainsaw, maintain a firm grip and a stable stance․ Keep a clear work area free from obstacles and bystanders․ Never operate the chainsaw while under the influence of drugs or alcohol, or when fatigued․ Be aware of the potential for kickback, and use proper cutting techniques to minimize the risk․ Avoid cutting above shoulder height or reaching excessively․
During operation, maintain constant awareness of your surroundings and the position of the chainsaw․ Use both hands to control the chainsaw at all times, and avoid distractions․ If the chainsaw becomes stuck or pinched, stop the engine and carefully remove it․ Store the chainsaw in a safe location, away from children and unauthorized users․ Regular maintenance and adherence to these safety precautions are essential for safe and efficient operation․
Starting and Stopping the Chainsaw
Starting your Stihl MS 251 correctly is crucial for its longevity and safe operation․ Begin by engaging the chain brake․ Place the saw on a stable, flat surface․ Activate the choke according to whether the engine is cold or warm․ For a cold start, fully engage the choke; for a warm start, use half-choke or no choke․
Hold the saw firmly with your left hand on the front handle․ Place your right foot through the rear handle to secure the saw․ Pull the starter cord handle sharply and smoothly until the engine sputters․ Once it sputters, disengage the choke gradually․ Continue pulling the starter cord until the engine starts and runs smoothly․
To stop the MS 251, simply move the master control lever to the “STOP” position․ Ensure the chain has completely stopped before setting the saw down․ If the engine doesn’t stop, use the choke to stall it․ Diagnose the issue before restarting․ Always engage the chain brake when the saw is not in use․ Proper starting and stopping procedures ensure safe and efficient operation․
Chain Brake System and Activation
The Stihl MS 251 features a crucial safety mechanism: the chain brake․ This system is designed to stop the chain immediately in the event of kickback, significantly reducing the risk of injury․ The MS 251’s chain brake can be activated in two primary ways: manually and by inertia․
Manual activation involves pushing the front hand guard forward towards the bar nose․ This action engages the brake band around the clutch drum, halting the chain’s rotation․ The second method is inertia activation․ During a kickback event, the inertia of the front hand guard automatically forces it forward, engaging the chain brake․
Before each use, test the chain brake to ensure it functions correctly․ Start the saw and engage the brake manually․ The chain should stop immediately․ If it doesn’t, have the brake system inspected and serviced by a qualified technician․ Regularly inspect the brake band and drum for wear or damage․ A properly functioning chain brake is essential for safe chainsaw operation․
Fueling and Lubrication Procedures
Proper fueling and lubrication are essential for the Stihl MS 251’s performance and longevity․ Use a high-quality 2-stroke engine oil specifically designed for air-cooled engines․ Mix the oil with unleaded gasoline at the ratio specified in the instruction manual․ Typically, this is a 50:1 ratio (gasoline to oil)․
Always mix the fuel in a separate, clean container․ Pour the correct amount of oil into the container first, then add the gasoline․ Shake the mixture thoroughly to ensure proper blending․ When fueling the chainsaw, use a funnel to prevent spills․ Avoid overfilling the fuel tank․
The MS 251 also requires chain oil for lubrication․ Use a high-quality chain oil to reduce friction and wear on the chain and bar․ Fill the chain oil reservoir before each use․ The MS 251 features an Ematic lubrication system, which optimizes oil consumption․ Regularly check the oil level and adjust the oiler output as needed, depending on the cutting conditions․
Maintenance and Servicing
Regular maintenance is crucial for keeping your Stihl MS 251 chainsaw in optimal condition; Before each use, inspect the chain for sharpness and proper tension․ Sharpen the chain regularly using a chain sharpener or file․ Check the air filter and clean or replace it as needed․ A clogged air filter can reduce engine performance․
Periodically inspect the spark plug and clean or replace it if necessary․ Maintain the cooling fins on the cylinder to prevent overheating․ Clean any debris from around the engine․ Check the fuel filter and replace it if it’s dirty or clogged․
The bar should be inspected for wear and damage․ File down any burrs or unevenness․ Regularly clean the bar groove to ensure proper chain lubrication․ For more complex servicing, refer to the Stihl MS 251 service manual or consult a qualified technician․ Proper maintenance will extend the life of your chainsaw and ensure safe operation․
Troubleshooting Common Issues
Even with proper maintenance, you may encounter issues with your Stihl MS 251․ If the chainsaw won’t start, check the fuel level, spark plug, and air filter․ Make sure the choke is in the correct position․ If the engine starts but stalls, the carburetor may need adjustment․ A dirty fuel filter can also cause stalling․
If the chain isn’t lubricating properly, check the oil level in the tank and ensure the bar oiler is functioning․ Clean the bar groove and oil passages․ A dull chain can cause the chainsaw to cut slowly or unevenly․ Sharpen the chain or replace it if necessary․
Overheating can be caused by a dirty air filter or clogged cooling fins․ Clean these components to improve airflow․ If the chainsaw vibrates excessively, check for loose screws or damaged parts․ Refer to the Stihl MS 251 manual for detailed troubleshooting steps and diagrams․ If you’re unable to resolve the issue, consult a qualified technician․
Available Manuals and Resources
To ensure the safe and efficient operation of your Stihl MS 251 chainsaw, it’s essential to have access to the correct manuals and resources․ The primary resource is the official Stihl MS 251 Instruction Manual․ This manual provides detailed information on safety precautions, operating procedures, maintenance schedules, and troubleshooting tips․
In addition to the instruction manual, a parts manual is available, offering exploded views of the chainsaw and detailed parts lists․ This is invaluable when ordering replacement parts or performing repairs․ Service manuals are also available, providing in-depth technical information for servicing and repairing the MS 251․
Online resources include the Stihl website, which offers downloadable manuals and product information․ Various online forums and communities dedicated to Stihl chainsaws can also provide helpful tips and advice from other users․ Local Stihl dealers are another valuable resource, offering expert advice, parts, and service․
Parts Diagrams and Exploded Views
Understanding the components of your Stihl MS 251 chainsaw is crucial for effective maintenance and repair․ Parts diagrams and exploded views provide a detailed visual representation of how each part fits together, making it easier to identify and locate specific components․
These diagrams typically show the chainsaw disassembled, with each part labeled and numbered․ This allows you to cross-reference the diagram with a parts list, which includes the part name and its corresponding part number․ Exploded views are particularly useful when disassembling and reassembling the chainsaw, as they show the correct order in which parts should be installed․
Access to these diagrams is essential when troubleshooting problems, ordering replacement parts, or performing repairs․ They can be found in the Stihl MS 251 service manual or parts manual, which are often available online as PDF downloads․ Additionally, many online retailers that sell Stihl parts provide parts diagrams on their websites․