How to Unflood a Stihl Chainsaw (3 Pro Tips Every Logger Uses)
Let’s face it, we’ve all been there. You’re out in the woods, ready to tackle a pile of logs, you pull the starter cord on your Stihl chainsaw, and… nothing. Or worse, it sputters, coughs, and then dies. Chances are, you’ve flooded it. Flooding a chainsaw, especially a Stihl, is a common problem that can bring your wood processing or firewood preparation project to a screeching halt. A common mistake I see is people panicking and just yanking on the starter cord repeatedly, which only makes the problem worse.
In this article, I’m going to share three pro tips that experienced loggers use to unflood a Stihl chainsaw quickly and efficiently. These aren’t just theoretical tricks; they’re techniques I’ve learned over years of working with chainsaws, from felling trees in dense forests to prepping firewood for long winters. I’ll break down the process step-by-step, explaining the “why” behind each action, and even share some personal anecdotes and insights I’ve gained along the way. So, let’s dive in and get your saw roaring again!
Understanding Flooding in Chainsaws
Before we jump into the solutions, let’s understand what flooding actually is. Flooding occurs when there’s too much fuel in the cylinder of your chainsaw’s engine. This excess fuel prevents the spark plug from igniting the air-fuel mixture, essentially drowning the engine.
Why Does Flooding Happen?
Several factors can contribute to flooding:
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Over-Priming: This is the most common culprit. The primer bulb is designed to draw fuel into the carburetor, making starting easier, especially in cold weather. However, pumping the primer bulb too many times forces excess fuel into the engine.
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Choke Problems: The choke restricts airflow to create a richer fuel mixture for cold starts. If the choke is engaged for too long after the engine has warmed up, it can lead to flooding.
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Warm Engine: Trying to start a warm engine with the choke engaged is a surefire way to flood it. The engine already has enough fuel, and adding more with the choke is overkill.
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Tipped Chainsaw: If the chainsaw is tipped over, especially with a full fuel tank, fuel can leak into the carburetor and flood the engine.
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Faulty Carburetor: In some cases, a malfunctioning carburetor can be the cause of flooding. A carburetor that’s leaking fuel or not regulating the fuel mixture properly will cause flooding.
Key Terms and Concepts
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Carburetor: The carburetor is responsible for mixing air and fuel in the correct proportions to create a combustible mixture for the engine.
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Primer Bulb: A small, transparent bulb that, when pressed, draws fuel from the fuel tank to the carburetor, making starting easier.
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Choke: A valve that restricts airflow to the carburetor, creating a richer fuel mixture for cold starts.
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Spark Plug: An electrical component that ignites the air-fuel mixture in the cylinder, causing combustion.
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Cylinder: The chamber in the engine where combustion occurs.
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Two-Stroke Engine: Chainsaws typically use two-stroke engines, which require a mixture of gasoline and oil.
Pro Tip #1: The “Purge and Pray” Method
This is often the first line of defense for a flooded Stihl chainsaw, and it’s based on a principle of clearing the excess fuel.
Step-by-Step Guide
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Disengage the Choke: Make sure the choke lever is in the “off” or “run” position. This allows maximum airflow into the engine.
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Full Throttle: Engage the throttle fully. This opens the throttle valve, allowing more air to enter the cylinder and help evaporate the excess fuel. Important Safety Note: Ensure the chain brake is engaged before attempting to start the chainsaw in this position.
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Pull the Starter Cord: Pull the starter cord repeatedly (5-10 times) with the throttle fully engaged. This forces air through the cylinder, helping to purge the excess fuel. Listen carefully for any signs of the engine trying to start.
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Release the Throttle: After several pulls with full throttle, release the throttle and try starting the chainsaw normally.
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Persistence is Key: If the chainsaw still doesn’t start, repeat steps 2-4 a few more times. Sometimes it takes a little persistence to clear the flood.
Why This Works
Engaging the throttle allows more air to enter the cylinder, while pulling the starter cord creates suction and pushes the excess fuel out through the exhaust port. The “pray” part comes in because sometimes, it just takes a little luck!
Personal Experience
I remember one particularly cold morning in the Adirondacks. I was cutting firewood with a group, and one of the guys kept flooding his Stihl MS 261. He was getting frustrated, and the rest of the crew were getting impatient. I stepped in and used the “purge and pray” method, and after about five attempts, the saw finally roared to life. The look on his face was priceless! He’d been yanking on the cord for 15 minutes with no luck.
Strategic Advantages
- Simple and Quick: This method is relatively simple and can often be done quickly in the field.
- Non-Invasive: It doesn’t require any tools or disassembly.
Potential Drawbacks
- Not Always Effective: This method doesn’t always work, especially if the engine is severely flooded.
- Can Be Tiring: Pulling the starter cord repeatedly can be tiring, especially on larger chainsaws.
Pro Tip #2: The “Spark Plug Inspection” Method
If the “Purge and Pray” method fails, it’s time to get a little more hands-on. This method involves inspecting the spark plug to see if it’s wet and fouled with fuel.
Step-by-Step Guide
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Safety First: Before you start, make sure the chainsaw is turned off and the chain brake is engaged. Let the chainsaw cool down if you’ve been trying to start it for a while.
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Locate the Spark Plug: The spark plug is usually located under a small cover on the side of the engine. Consult your chainsaw’s owner’s manual if you’re unsure of its location.
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Remove the Spark Plug Cover: Use a screwdriver or wrench to remove the spark plug cover.
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Disconnect the Spark Plug Wire: Carefully disconnect the spark plug wire from the spark plug.
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Remove the Spark Plug: Use a spark plug wrench to carefully remove the spark plug from the cylinder head.
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Inspect the Spark Plug: Examine the spark plug. If it’s wet with fuel, it’s a sign of flooding. Also, check for any signs of fouling (carbon buildup) on the electrode.
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Dry the Spark Plug: If the spark plug is wet, dry it thoroughly with a clean cloth or paper towel. You can also use a wire brush to clean any carbon buildup. Some people even use a lighter to burn off the excess fuel, but be extremely careful if you choose to do this!
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Purge the Cylinder (Again): With the spark plug removed, pull the starter cord several times to help purge any remaining fuel from the cylinder.
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Reinstall the Spark Plug: Carefully reinstall the spark plug into the cylinder head, tightening it with the spark plug wrench. Don’t overtighten it!
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Reconnect the Spark Plug Wire: Reconnect the spark plug wire to the spark plug.
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Reinstall the Spark Plug Cover: Reinstall the spark plug cover.
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Attempt to Start the Chainsaw: Try starting the chainsaw normally, with the choke in the correct position.
Why This Works
Removing the spark plug allows you to physically dry it, ensuring that it can produce a spark. Purging the cylinder with the spark plug removed helps to remove any remaining fuel from the engine.
Personal Experience
I once had a Stihl MS 462 that I’d flooded so badly I thought I’d broken it. I’d been trying to start it for almost an hour with no luck. I finally decided to pull the spark plug, and it was soaked! I cleaned it up, purged the cylinder, and the saw started on the second pull. It was a huge relief.
Strategic Advantages
- More Thorough: This method is more thorough than the “Purge and Pray” method and is more likely to be effective.
- Allows Inspection: It allows you to inspect the spark plug for signs of fouling, which can indicate other problems.
Potential Drawbacks
- Requires Tools: This method requires a spark plug wrench and possibly a screwdriver.
- More Time-Consuming: It takes more time than the “Purge and Pray” method.
- Risk of Damage: There is a slight risk of damaging the spark plug or cylinder head if you’re not careful.
Pro Tip #3: The “Air It Out” Method (For the Seriously Flooded)
This method is for situations where the chainsaw is severely flooded and the previous two methods have failed. It’s a bit more involved, but it can be a lifesaver. This method focuses on letting the engine air out thoroughly to evaporate the excess fuel.
Step-by-Step Guide
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Safety First (Again): As always, make sure the chainsaw is turned off and the chain brake is engaged. Let the chainsaw cool down completely.
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Remove the Air Filter: Locate the air filter cover and remove it. Then, remove the air filter itself. This allows for maximum airflow into the carburetor.
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Remove the Spark Plug (Again): Follow steps 2-5 from the “Spark Plug Inspection” method to remove the spark plug.
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Open the Throttle: Engage the throttle fully. This opens the throttle valve, allowing more air to circulate through the engine.
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Leave It Alone: This is the crucial part. Find a dry, well-ventilated place to leave the chainsaw for several hours, or even overnight. The goal is to allow the excess fuel to evaporate completely.
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Reassemble: After the engine has had plenty of time to air out, reassemble the chainsaw by reinstalling the spark plug, air filter, and covers.
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Attempt to Start: Try starting the chainsaw normally, with the choke in the correct position. You might need to pull the starter cord several times to prime the fuel system.
Why This Works
This method allows the excess fuel to evaporate naturally, rather than relying on force to purge it. By removing the air filter and spark plug, and opening the throttle, you maximize airflow and accelerate the evaporation process.
Personal Experience
I once had a Stihl 026 that I’d managed to flood so badly that I thought it was a goner. I’d tried everything, but nothing worked. I was about to give up and take it to a repair shop, but then I decided to try the “air it out” method. I left the saw in my garage overnight, and the next morning, it started on the first pull! I was amazed.
Strategic Advantages
- Effective for Severe Flooding: This method is often effective when other methods have failed.
- Gentle on the Engine: It doesn’t involve any forceful purging or manipulation of the engine.
Potential Drawbacks
- Time-Consuming: This method requires a significant amount of time.
- Requires Patience: You need to be patient and allow the engine to air out completely.
Preventing Flooding in the First Place
While knowing how to unflood a chainsaw is essential, it’s even better to prevent flooding in the first place. Here are some tips:
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Prime Sparingly: Only prime the engine a few times, especially in warm weather. Over-priming is the most common cause of flooding.
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Use the Choke Correctly: Use the choke only for cold starts, and disengage it as soon as the engine starts to warm up.
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Avoid Tipping: Be careful not to tip the chainsaw over, especially when the fuel tank is full.
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Maintain Your Chainsaw: Regularly service your chainsaw, including cleaning the air filter and inspecting the spark plug. A clean air filter ensures proper airflow, and a healthy spark plug ensures proper ignition.
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Use Fresh Fuel: Use fresh, high-quality fuel mixed with the correct ratio of two-stroke oil. Old or contaminated fuel can cause starting problems, including flooding. I personally use a fuel stabilizer to keep my fuel fresh for longer.
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Store Your Chainsaw Properly: Store your chainsaw in a dry, well-ventilated place. If you’re not going to use it for a long period, drain the fuel tank completely.
Case Study: Unflooding a Stihl MS 271 Farm Boss
Let’s walk through a real-world scenario using a Stihl MS 271 Farm Boss, a popular model for both homeowners and professional users.
Scenario: You’ve been cutting firewood for about an hour, and the MS 271 starts to bog down. You stop the saw to refuel, and when you try to restart it, it just sputters and dies. You realize you’ve likely flooded it.
Solution:
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Initial Assessment: First, I check the choke lever. It’s in the “off” position, so that’s not the immediate problem. I suspect over-priming, as I might have been a little too enthusiastic with the primer bulb after refueling.
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Attempt “Purge and Pray”: I engage the chain brake for safety. I then engage the throttle fully and pull the starter cord about 8 times. I listen carefully, but there’s no sign of the engine catching.
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“Spark Plug Inspection”: Since the first method failed, I move on to inspecting the spark plug. I turn off the chainsaw completely and let it cool down for a few minutes. I locate the spark plug cover on the side of the engine and remove it using a screwdriver. I disconnect the spark plug wire and use a spark plug wrench to remove the spark plug.
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Diagnosis: The spark plug is definitely wet with fuel. There’s also a bit of carbon buildup on the electrode.
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Cleaning and Purging: I dry the spark plug thoroughly with a clean rag and use a wire brush to clean off the carbon buildup. With the spark plug removed, I pull the starter cord about 5 times to purge the cylinder.
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Reassembly and Restart: I carefully reinstall the spark plug, reconnect the spark plug wire, and reinstall the spark plug cover. I set the choke to the “cold start” position and pull the starter cord. After a few pulls, the engine sputters to life. I immediately disengage the choke, and the engine runs smoothly.
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Preventative Measures: To prevent flooding in the future, I make a mental note to be more conservative with the primer bulb and ensure the choke is disengaged promptly after starting.
Lessons Learned: This case study highlights the importance of a systematic approach to unflooding a chainsaw. Starting with the simplest method and progressing to more involved techniques can save you time and frustration. Also, identifying the root cause of the flooding (in this case, likely over-priming) can help prevent it from happening again.
Choosing the Right Tools and Materials
Having the right tools and materials on hand can make unflooding a chainsaw much easier and more efficient. Here’s a list of essential items:
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Spark Plug Wrench: A spark plug wrench is specifically designed to remove and install spark plugs without damaging them. Make sure you have the correct size for your chainsaw.
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Screwdriver: A screwdriver is needed to remove the spark plug cover and other components.
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Clean Rags or Paper Towels: Clean rags or paper towels are essential for drying the spark plug and cleaning up any spilled fuel.
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Wire Brush: A wire brush is useful for cleaning carbon buildup from the spark plug electrode.
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Fuel Stabilizer: Fuel stabilizer helps to keep your fuel fresh for longer, preventing starting problems.
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Two-Stroke Oil: Use high-quality two-stroke oil mixed with gasoline at the correct ratio.
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Owner’s Manual: Your chainsaw’s owner’s manual contains valuable information about troubleshooting and maintenance.
Drying Methods for Firewood
While not directly related to unflooding a chainsaw, proper firewood drying is essential for efficient burning and preventing problems with your wood stove or fireplace. Here are some key points:
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Green Wood vs. Seasoned Wood: Green wood is freshly cut wood that has a high moisture content. Seasoned wood has been dried for a period of time, reducing its moisture content. Seasoned wood burns much more efficiently and produces less smoke.
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Moisture Content Targets: The ideal moisture content for firewood is between 15% and 20%. You can use a moisture meter to measure the moisture content of your firewood.
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Drying Time: The drying time for firewood depends on the type of wood, the size of the pieces, and the climate. Generally, it takes at least six months to a year to properly season firewood.
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Stacking Methods: Proper stacking is crucial for efficient drying. Stack the wood in a single row, off the ground, and with plenty of air circulation. Cover the top of the stack to protect it from rain and snow.
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Wood Type Selection: Different types of wood have different drying times and burning characteristics. Hardwoods like oak and maple are denser and burn longer than softwoods like pine and fir.
Safety Considerations
Working with chainsaws and firewood can be dangerous, so it’s important to take safety precautions.
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Wear Proper Safety Gear: Always wear safety glasses, hearing protection, gloves, and sturdy boots when operating a chainsaw.
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Use the Chain Brake: Always engage the chain brake when the chainsaw is not in use.
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Be Aware of Your Surroundings: Be aware of your surroundings and avoid cutting in areas where there are people or obstacles.
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Never Cut Above Your Head: Never cut above your head, as this is extremely dangerous.
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Maintain Your Chainsaw Properly: Regularly service your chainsaw and keep the chain sharp.
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Take Breaks: Take frequent breaks to avoid fatigue.
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Read the Owner’s Manual: Read and understand your chainsaw’s owner’s manual before operating it.
Conclusion: From Flooded to Firing on All Cylinders
Unflooding a Stihl chainsaw doesn’t have to be a frustrating experience. By understanding the causes of flooding and following these three pro tips, you can quickly get your saw back up and running. Remember to start with the simplest method (the “Purge and Pray” method) and progress to more involved techniques if necessary. And most importantly, take preventative measures to avoid flooding in the first place.
Now that you’re armed with this knowledge, you can confidently tackle your wood processing and firewood preparation projects without fear of being sidelined by a flooded chainsaw. So, get out there, stay safe, and keep your saw roaring! Remember, practice makes perfect, and with a little patience and persistence, you’ll become a chainsaw troubleshooting pro in no time. Good luck, and happy cutting!
