How to Start Stihl MS250 (7 Pro Tips for Trouble-Free Ignition)

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How to Start Your Stihl MS250: 7 Pro Tips for Trouble-Free Ignition

The Stihl MS250. Just the name evokes images of perfectly stacked firewood, meticulously cleared trails, and the satisfaction of a job well done. It’s more than just a chainsaw; it’s a dependable partner in turning raw timber into something useful and beautiful. I’ve personally spent countless hours with my MS250, felling trees for sustainable firewood, clearing storm damage, and even using it for artistic wood carving projects.

That’s why I’ve compiled this guide – not just a list of instructions, but a collection of hard-earned knowledge, personal experiences, and proven techniques to ensure your Stihl MS250 starts reliably every single time. Forget the frustration of endless pulling; let’s get your saw roaring to life with these seven pro tips.

Key Takeaways:

• Fuel Freshness is Paramount: Old fuel is the enemy. Learn why and how to prevent it.
• Master the Starting Sequence: Understand the choke, throttle lock, and recoil pull process.
• Spark Plug Inspection is Crucial: A fouled or damaged spark plug is a common culprit.
• Air Filter Maintenance is Key: A clean air filter ensures proper air-fuel mixture.
• Warm-Up is Essential: Don’t rush into full throttle; let your saw warm up properly.
• Flooding Prevention is a Must: Know how to recognize and clear a flooded engine.
• Proper Storage Matters: Learn the best practices for storing your MS250 to prevent future starting problems.

The Luxury of a Reliable Chainsaw

Think about it: the ability to transform a fallen tree into a winter’s worth of warmth, the independence of clearing your own land, the sheer satisfaction of shaping wood to your will. That’s the luxury a reliable chainsaw like the Stihl MS250 offers. But this luxury is quickly diminished when you’re yanking on the starter cord, sweat dripping down your brow, with nothing but a stubborn engine for your efforts.

I remember one particularly harsh winter where a massive ice storm downed several trees on my property. My wood stove was my primary heat source, and the prospect of a cold house was a serious concern. My MS250, usually a trusty workhorse, refused to start. After an hour of troubleshooting, I discovered the fuel line had cracked from the cold. That experience taught me the importance of preventative maintenance and understanding the intricacies of chainsaw ignition.

This article is born from those experiences, combined with years of research and conversations with seasoned loggers and small engine mechanics. I’m going to share everything I know to help you avoid similar frustrations and unlock the true potential of your Stihl MS250.

1. Fuel Freshness: The Lifeblood of Your MS250

Let’s start with the foundation: fuel. I can’t stress enough how critical fresh fuel is for reliable starting. Ethanol-blended gasoline, commonly found at most gas stations, is a notorious culprit for causing starting problems in small engines.

The Ethanol Problem:

Ethanol attracts moisture, leading to phase separation. This means the ethanol and water separate from the gasoline, creating a gummy residue that clogs fuel lines, carburetors, and fuel filters. Furthermore, ethanol can corrode rubber and plastic components in your fuel system.

Data-Backed Insights:

• Studies by the Outdoor Power Equipment Institute (OPEI) have shown that using fuel with more than 10% ethanol (E10) can cause significant damage to small engines not designed for it.
• A survey of small engine repair shops revealed that over 70% of carburetor-related repairs are due to the use of stale or ethanol-blended fuel.

My Recommendation:

• Use Ethanol-Free Fuel: Whenever possible, use ethanol-free gasoline. It’s usually available at marinas or specialty gas stations. Look for fuel with an octane rating of 89 or higher.
• Use Fuel Stabilizer: If you must use ethanol-blended fuel, add a fuel stabilizer specifically designed for small engines. I personally use Stihl’s MotoMix, a pre-mixed fuel with stabilizer, or STA-BIL Fuel Stabilizer.
• Mix Fuel Correctly: If you’re mixing your own two-stroke fuel, use the correct oil-to-fuel ratio. For the Stihl MS250, it’s typically 50:1 (50 parts gasoline to 1 part two-stroke oil). Always use high-quality two-stroke oil specifically formulated for air-cooled engines.
• Store Fuel Properly: Store fuel in a tightly sealed container in a cool, dry place. Avoid storing fuel for more than 30 days, especially if it contains ethanol.
• Drain Before Storage: If you know you won’t be using your chainsaw for an extended period (e.g., over the winter), drain the fuel tank and run the engine until it stalls to remove any remaining fuel from the carburetor.

Personal Story:

I once neglected to drain the fuel from my MS250 before storing it for the winter. The following spring, I spent hours trying to get it started, only to discover that the carburetor was completely gummed up with residue from the old fuel. A costly carburetor cleaning and rebuild could have been avoided with a simple fuel drain.

2. Mastering the Starting Sequence: The Right Steps, Every Time

The Stihl MS250 has a specific starting sequence that needs to be followed precisely. Deviation from this sequence is a common cause of starting problems.

Step-by-Step Starting Procedure:

1. Fuel the Saw: Ensure the fuel tank is properly filled with fresh fuel.
2. Activate the Chain Brake: Engage the chain brake by pushing the front hand guard forward. This is a crucial safety step.
3. Choke Engagement (Cold Start): For a cold engine, fully engage the choke by pulling the choke lever all the way out. This restricts airflow, enriching the fuel mixture for easier starting.
4. Throttle Lock (Starting Throttle Position): Set the throttle to the starting position. On the MS250, this is typically done by pushing the master control lever down one position after engaging the choke.
5. Secure Footing: Place the chainsaw on a firm, flat surface. Hold the front handle firmly with your left hand and place your right foot through the rear handle for stability.
6. Recoil Pull: Grasp the starter handle firmly and pull the cord out slowly until you feel resistance. Then, give it a sharp, full pull. Do not pull the cord all the way out.
7. Listen for a “Pop”: After a few pulls, you should hear a “pop” or a brief attempt to start. This indicates that fuel is reaching the cylinder.
8. Disengage Choke: Immediately push the choke lever in one position. This allows more air into the mixture.
9. Recoil Pull (Continued): Continue pulling the starter cord until the engine starts and runs smoothly.
10. Warm-Up: Let the engine idle for a few minutes to warm up before engaging the chain and cutting.
11. Disengage Chain Brake: Once the engine is running smoothly, disengage the chain brake by pulling the front hand guard back towards you.

Troubleshooting Starting Issues:

• No “Pop”: If you don’t hear a “pop” after several pulls with the choke engaged, the engine may not be getting fuel. Check the fuel lines for kinks or blockages, and ensure the fuel filter is clean.
• Engine Starts Briefly and Dies: This could indicate a lean fuel mixture. Try adjusting the carburetor settings (if you’re comfortable doing so) or consult a qualified mechanic.
• Engine Floods: If you pull the starter cord excessively with the choke engaged, you may flood the engine. Refer to Section 6 for instructions on clearing a flooded engine.

Expert Quote:

“The starting sequence is like a dance,” says veteran logger Jim Harrison. “Each step is crucial, and if you miss a beat, the whole thing falls apart. Pay attention to the sounds and feel of the engine; it will tell you what it needs.”

3. Spark Plug Inspection: Igniting the Power

The spark plug is the heart of the ignition system. A fouled, damaged, or improperly gapped spark plug can prevent the engine from starting or cause it to run poorly.

Spark Plug Inspection Procedure:

1. Locate the Spark Plug: The spark plug is typically located on the side of the engine, near the cylinder head.
2. Remove the Spark Plug Boot: Carefully pull the spark plug boot off the spark plug.
3. Remove the Spark Plug: Use a spark plug wrench to loosen and remove the spark plug.
4. Inspect the Spark Plug: Examine the spark plug for the following:
   • Cracks or Damage: Look for any cracks in the porcelain insulator or damage to the electrode.
   • Fouling: Check for excessive carbon buildup, oil deposits, or fuel residue on the electrode.
   • Electrode Wear: Inspect the electrode for excessive wear or rounding.
5. Clean the Spark Plug: If the spark plug is fouled, clean it with a wire brush or spark plug cleaner.
6. Gap the Spark Plug: Use a spark plug gapping tool to ensure the electrode gap is set to the manufacturer’s specifications. For the Stihl MS250, the gap is typically around 0.020 inches (0.5 mm).
7. Reinstall the Spark Plug: Carefully reinstall the spark plug and tighten it to the manufacturer’s specified torque.
8. Reattach the Spark Plug Boot: Securely reattach the spark plug boot.

Data-Backed Insights:

• A study by a leading spark plug manufacturer found that replacing spark plugs at recommended intervals can improve fuel efficiency by up to 4% and reduce emissions by up to 10%.
• Spark plug fouling is a common issue in two-stroke engines due to the oil mixed with the fuel.

My Recommendation:

• Replace Spark Plugs Regularly: Replace the spark plug on your Stihl MS250 at least once a year, or more frequently if you use the saw heavily.
• Use the Correct Spark Plug: Use the spark plug recommended by Stihl for the MS250. Using the wrong spark plug can damage the engine.
• Carry a Spare Spark Plug: Keep a spare spark plug in your toolkit so you can quickly replace a fouled or damaged plug in the field.

Personal Story:

I was once cutting firewood deep in the woods when my MS250 suddenly died. After checking the fuel and air filter, I discovered that the spark plug was completely fouled with carbon deposits. Fortunately, I had a spare spark plug in my toolkit, and I was able to get the saw running again in a matter of minutes. That experience taught me the importance of being prepared for unexpected problems.

4. Air Filter Maintenance: Breathing Easy for Peak Performance

A clean air filter is essential for proper engine performance. A clogged air filter restricts airflow, causing the engine to run rich (too much fuel, not enough air), which can lead to starting problems, reduced power, and increased emissions.

Air Filter Cleaning Procedure:

1. Locate the Air Filter: The air filter is typically located under a cover on top of the engine.
2. Remove the Air Filter Cover: Remove the air filter cover by unscrewing the retaining screws or releasing the clips.
3. Remove the Air Filter: Carefully remove the air filter.
4. Inspect the Air Filter: Examine the air filter for dirt, dust, and debris.
5. Clean the Air Filter:
   • Foam Air Filter: Wash the foam air filter in warm, soapy water. Rinse thoroughly and allow it to air dry completely. After drying, lightly oil the filter with air filter oil.
   • Felt or Paper Air Filter: Tap the filter gently to remove loose dirt and debris. If the filter is heavily soiled, replace it with a new one. Do not wash paper or felt air filters.
6. Reinstall the Air Filter: Carefully reinstall the air filter.
7. Reinstall the Air Filter Cover: Reinstall the air filter cover and secure it with the retaining screws or clips.

Data-Backed Insights:

• Studies have shown that a clogged air filter can reduce engine power by up to 10% and increase fuel consumption by up to 15%.
• Operating a chainsaw with a dirty air filter can significantly shorten the engine’s lifespan.

My Recommendation:

• Clean the Air Filter Regularly: Clean the air filter on your Stihl MS250 after every 5-10 hours of use, or more frequently if you’re working in dusty conditions.
• Replace Air Filters When Necessary: Replace the air filter if it’s damaged, excessively soiled, or cannot be cleaned effectively.
• Use Genuine Stihl Air Filters: Use genuine Stihl air filters to ensure proper fit and performance.

Personal Story:

I once spent an entire day trying to diagnose a starting problem on my MS250. I checked the fuel, spark plug, and carburetor, but nothing seemed to work. Finally, I decided to inspect the air filter, and I was shocked to find it completely clogged with sawdust and debris. After cleaning the air filter, the saw started right up and ran perfectly. That experience taught me the importance of not overlooking the simple things.

5. Warm-Up is Essential: Patience Pays Off

Just like a car engine, a chainsaw engine needs to warm up properly before being subjected to heavy loads. Rushing into full throttle before the engine has reached operating temperature can cause premature wear and tear, and can also make starting more difficult in the long run.

Warm-Up Procedure:

1. Start the Engine: Follow the starting procedure outlined in Section 2.
2. Allow to Idle: Let the engine idle for 2-3 minutes after starting. During this time, the engine will gradually warm up to operating temperature.
3. Monitor Engine Performance: Listen to the engine and watch for any signs of hesitation or stalling. If the engine stalls, restart it and allow it to warm up for a longer period.
4. Gradual Throttle Increase: After the initial warm-up period, gradually increase the throttle speed. Avoid sudden bursts of full throttle.
5. Cutting Test: Before starting any serious cutting, perform a test cut on a small piece of wood to ensure the engine is running smoothly and the chain is properly lubricated.

Data-Backed Insights:

• Engine wear is significantly higher during cold starts due to increased friction and reduced lubrication.
• Allowing an engine to warm up properly can extend its lifespan by up to 20%.

My Recommendation:

• Be Patient: Resist the urge to start cutting immediately after starting the engine. Give it a few minutes to warm up properly.
• Adjust Carburetor if Needed: If the engine consistently stalls during warm-up, you may need to adjust the carburetor settings. Consult a qualified mechanic if you’re not comfortable doing this yourself.
• Use the Right Oil: Use high-quality two-stroke oil specifically formulated for air-cooled engines. This will ensure proper lubrication during warm-up.

Personal Story:

I used to be impatient and would often start cutting firewood immediately after starting my MS250. I noticed that the saw would often bog down and stall, and it seemed to be losing power over time. After talking to a mechanic, I learned that I was causing premature wear and tear on the engine by not allowing it to warm up properly. Since then, I’ve made a conscious effort to let the saw warm up before cutting, and I’ve noticed a significant improvement in its performance and longevity.

6. Flooding Prevention: Avoiding the Fuel-Saturated Nightmare

Flooding occurs when too much fuel enters the cylinder, preventing the spark plug from igniting the air-fuel mixture. This is a common problem with chainsaws, especially when starting a cold engine.

Symptoms of a Flooded Engine:

• The engine will not start, even after repeated pulls on the starter cord.
• The spark plug may be wet with fuel.
• You may smell a strong odor of gasoline.

Clearing a Flooded Engine:

1. Remove the Spark Plug: Remove the spark plug and inspect it for fuel. If it’s wet, dry it with a clean cloth.
2. Pull the Starter Cord (Without Choke): With the spark plug removed, pull the starter cord several times to clear excess fuel from the cylinder.
3. Reinstall the Spark Plug: Reinstall the spark plug and tighten it to the manufacturer’s specified torque.
4. Start the Engine (Without Choke): Attempt to start the engine without engaging the choke.
5. Gradually Engage Choke (If Necessary): If the engine still doesn’t start, gradually engage the choke until the engine starts and runs smoothly.
6. Avoid Over-Choking: Be careful not to over-choke the engine, as this can cause it to flood again.

Data-Backed Insights:

• Flooding is more common in cold weather due to the increased fuel enrichment required for cold starting.
• Excessive priming can also lead to flooding.

My Recommendation:

• Avoid Over-Choking: Only use the choke when necessary for cold starting.
• Prime Sparingly: If your chainsaw has a primer bulb, only prime it a few times before attempting to start the engine.
• Learn to Recognize the Signs of Flooding: Pay attention to the sounds and smell of the engine so you can recognize the signs of flooding early on.

Personal Story:

I once flooded my MS250 so badly that I thought I had ruined it. I had been pulling on the starter cord for what seemed like an eternity, and the engine just wouldn’t start. I was about to give up when I remembered reading about how to clear a flooded engine. I followed the steps outlined above, and to my surprise, the saw started right up. That experience taught me the importance of knowing how to deal with common chainsaw problems.

7. Proper Storage Matters: Protecting Your Investment

Proper storage is crucial for preventing starting problems and extending the lifespan of your Stihl MS250.

Storage Best Practices:

1. Drain the Fuel Tank: Drain the fuel tank completely to prevent fuel from deteriorating and causing problems in the carburetor.
2. Run the Engine Dry: Start the engine and let it run until it stalls to remove any remaining fuel from the carburetor.
3. Remove the Spark Plug: Remove the spark plug and pour a small amount of two-stroke oil into the cylinder. Pull the starter cord a few times to distribute the oil, then reinstall the spark plug.
4. Clean the Chainsaw: Clean the chainsaw thoroughly to remove any dirt, dust, or debris.
5. Store in a Dry Place: Store the chainsaw in a dry, well-ventilated place. Avoid storing it in damp or humid environments, as this can cause rust and corrosion.
6. Protect from Extreme Temperatures: Avoid storing the chainsaw in direct sunlight or in extremely hot or cold temperatures.
7. Store the Chain Separately: Remove the chain and store it separately in a container of oil to prevent rust.
8. Cover the Chainsaw: Cover the chainsaw with a protective cover to prevent dust and debris from entering the engine.

Data-Backed Insights:

• Improper storage is a leading cause of carburetor problems in small engines.
• Protecting your chainsaw from the elements can significantly extend its lifespan.

My Recommendation:

• Follow the Manufacturer’s Recommendations: Refer to the Stihl MS250 owner’s manual for specific storage recommendations.
• Use a Chainsaw Storage Bag: Invest in a chainsaw storage bag to protect your saw from dust, dirt, and moisture.
• Inspect Before Use: Before using your chainsaw after a period of storage, inspect it thoroughly for any signs of damage or deterioration.

Personal Story:

I used to simply toss my MS250 in the corner of my garage after each use, without taking any precautions for storage. As a result, I often had starting problems and other issues. After learning about the importance of proper storage, I started following the steps outlined above. I’ve noticed a significant improvement in the reliability and longevity of my chainsaw.

Conclusion: Ignite Your Woodworking Passion

Starting a Stihl MS250 doesn’t have to be a struggle. By following these seven pro tips, you can ensure trouble-free ignition every time and unlock the full potential of this powerful and versatile chainsaw. Remember, fresh fuel, proper starting sequence, spark plug maintenance, air filter cleaning, warm-up, flooding prevention, and proper storage are all essential for reliable performance.

Now, armed with this knowledge, go forth and conquer your wood processing projects. Whether you’re felling trees for firewood, clearing land, or creating beautiful wood carvings, your Stihl MS250 will be ready to roar to life whenever you need it.

Actionable Next Steps:

• Check Your Fuel: Is your fuel fresh? If not, drain it and replace it with fresh fuel.
• Review the Starting Sequence: Practice the starting sequence until it becomes second nature.
• Inspect Your Spark Plug and Air Filter: Are they clean and in good condition? If not, clean or replace them.
• Prepare for Storage: If you’re not planning on using your chainsaw for an extended period, follow the storage best practices outlined above.

By taking these steps, you’ll be well on your way to enjoying the luxury of a reliable and powerful Stihl MS250 for years to come. Happy cutting!

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