A Stihl chainsaw that won’t start often leaves users frustrated, especially when it’s a flooded engine. What is a flooded chainsaw, and can I fix a flooded Stihl myself? Yes, a flooded chainsaw is one where too much fuel has entered the engine’s combustion chamber, preventing it from igniting. Fortunately, you can often fix a flooded Stihl with a few straightforward steps. This guide will walk you through how to start a flooded Stihl chainsaw and troubleshoot common Stihl starting issues that lead to a flooded engine.
Deciphering the Flooded Chainsaw Scenario
When your Stihl chainsaw refuses to fire up, and you suspect it’s flooded, it means the air-fuel mixture in the cylinder is too rich – there’s too much gas and not enough air. This is a common problem, especially if you’ve tried starting it multiple times without success, or if it was recently running and then stopped abruptly.
Why Chainsaws Flood
Several factors can contribute to a Stihl chainsaw starting issues flooded:
- Over-Choking: The most frequent culprit is prolonged use of the choke. If you engage the choke and pull the starter cord too many times, excess fuel can be drawn into the engine.
- Incorrect Fuel Mixture: Using a fuel-oil mixture that is too rich in oil can also lead to an inefficient burn and potential flooding.
- Carburetor Issues: A dirty or improperly adjusted carburetor can deliver too much fuel. This is a common problem with a flooded carburetor Stihl owners might encounter.
- Faulty Spark Plug: A fouled or wet spark plug won’t generate a strong spark, leading to incomplete combustion and potential fuel buildup.
- Improper Storage: Storing a chainsaw with fuel in the tank for extended periods, especially in fluctuating temperatures, can lead to fuel degradation and carb issues.
- Engine Overheating: While less common for causing flooding directly, an overheated engine can sometimes exhibit symptoms that mimic a flooded condition.
Recognizing the Signs of a Flooded Stihl
Before you attempt to start a flooded Stihl chainsaw, it’s helpful to identify the signs:
- Fuel Smell: A strong, persistent smell of gasoline is a dead giveaway.
- Difficulty in Starting: The engine might crank over but not catch, or it might sputter and die immediately.
- Wet Spark Plug: If you remove the spark plug, it might appear wet with fuel.
- Engine Misfiring: Even if it starts, it might run rough, sputter, or die quickly.
How to Start a Flooded Stihl Chainsaw: The Step-by-Step Guide
If your Stihl chainsaw won’t start flooded, follow these steps to clear a flooded chainsaw and get it running again. This procedure is designed to unflood chainsaw engines effectively.
Step 1: Disengage the Choke
This is the most crucial step to clear a flooded chainsaw.
- Locate the Choke Lever: Find the choke lever on your Stihl model. It’s usually near the carburetor or throttle control.
- Move the Choke to the “Run” or “Off” Position: This allows more air into the engine, helping to dry out the excess fuel.
Step 2: Remove the Spark Plug
This allows the excess fuel to evaporate and provides access to check the plug itself.
- Locate the Spark Plug: It’s usually at the top of the engine, under a protective cover.
- Remove the Spark Plug Wire: Gently pull the spark plug wire boot off the spark plug.
- Use a Spark Plug Wrench: Fit the correct size wrench onto the spark plug and turn it counter-clockwise to loosen and remove it.
Step 3: Dry the Spark Plug
A wet spark plug is a common reason why a flooded Stihl won’t start.
- Inspect the Spark Plug: Look for any signs of fuel or carbon fouling on the electrode.
- Wipe it Dry: Use a clean, lint-free cloth to thoroughly dry the spark plug.
- Clean if Necessary: If the spark plug is heavily fouled with carbon or oil, you might need to clean it with a wire brush or replace it with a new one. Ensure the gap is set correctly according to your Stihl manual.
Step 4: Clear Excess Fuel from the Cylinder
This is how you directly address the flooding.
- Turn the Chainsaw Upside Down: With the spark plug removed, carefully turn the chainsaw so the spark plug opening faces downwards. This helps gravity assist in draining excess fuel.
- Pull the Starter Rope: Give the starter rope a few gentle pulls (3-5 times). This helps to expel any liquid fuel from the cylinder through the spark plug hole. Be cautious not to pull too aggressively, as this can create a vacuum that might draw more fuel in.
Step 5: Reinstall the Spark Plug
Once you’ve cleared the excess fuel, it’s time to put things back together.
- Screw in the Spark Plug: Carefully thread the spark plug back into its housing by hand to avoid cross-threading.
- Tighten with Wrench: Use the spark plug wrench to tighten it firmly, but do not overtighten.
- Reconnect the Spark Plug Wire: Push the spark plug wire boot back onto the spark plug until it clicks into place.
Step 6: Attempt to Start the Chainsaw
Now, try to restart the engine.
- Set the Choke (If Applicable): For a flooded Stihl, you generally do not want to use the choke. Ensure it’s in the “Run” or “Off” position. Some models might have a “cold start” position that uses less choke than a full choke, which could be tried if the engine still sputters.
- Prime the Fuel Bulb (If Equipped): If your Stihl has a primer bulb, press it a few times until you see fuel returning to the bulb.
- Pull the Starter Rope: Give the starter rope a few firm pulls. The engine should now fire up. It might sputter initially as residual fuel burns off.
Step 7: Warm-Up the Engine
Once it starts, allow the engine to run for a minute or two to clear out any remaining moisture or fuel.
- Keep the Choke Off: Ensure the choke remains in the “Run” position.
- Gentle Throttle Application: Gradually apply a little throttle to help the engine reach a stable idle.
Troubleshooting Persistent Stihl Starting Issues Flooded
If the above steps don’t resolve the problem and you’re still facing Stihl starting issues flooded, consider these additional troubleshooting tips.
Addressing a Flooded Carburetor Stihl
A flooded carburetor Stihl owners often contend with requires specific attention.
- Allow Time for Evaporation: If you suspect the carburetor is flooded, leave the chainsaw idle for at least 15-30 minutes with the spark plug removed. This allows any excess fuel in the carburetor to evaporate.
- Check the Carburetor Adjustment Screws: Ensure the idle speed and mixture screws are set to the manufacturer’s specifications. Incorrect settings can lead to a fuel-rich mixture.
- Clean the Carburetor: If the problem persists, the carburetor might need cleaning or rebuilding. This can involve disassembling the carburetor, cleaning out jets and passages with a carburetor cleaner or compressed air, and replacing any worn gaskets or diaphragms. For this, it’s often best to consult your Stihl owner’s manual or seek professional assistance.
How to Dry a Flooded Chainsaw (Beyond the Spark Plug)
Sometimes, the fuel doesn’t just sit in the cylinder.
- Check the Air Filter: A saturated air filter can restrict airflow, leading to a rich mixture. Remove and inspect the air filter. If it’s wet with fuel, let it dry completely or replace it if it’s damaged.
- Inspect the Fuel Lines: Ensure there are no kinks or blockages in the fuel lines.
When to Seek Professional Help
If you’ve followed all these steps and your Stihl chainsaw still won’t start, it might be time to take it to an authorized Stihl service center. There could be more complex issues, such as:
- Ignition System Problems: A weak spark or no spark at all.
- Internal Engine Damage: Less likely, but possible.
- Faulty Carburetor: Requiring professional diagnosis and repair.
Preventing Your Stihl Chainsaw From Flooding
Preventing a flooded Stihl starting procedure is always better than fixing one.
Proper Choke Usage
- Cold Starts: Always use the choke for cold starts. Pull the starter rope a few times until the engine sputters, then immediately disengage the choke.
- Warm Starts: For a warm engine, usually no choke or only a brief “cold start” position is needed.
- Don’t Over-Choke: Resist the urge to keep pulling the starter rope with the choke fully engaged.
Maintaining the Fuel System
- Use Fresh Fuel: Always use fresh, properly mixed fuel. Old fuel can degrade and cause starting problems.
- Correct Fuel-Oil Ratio: Adhere strictly to the recommended fuel-oil ratio specified in your Stihl manual.
- Clean Fuel Filter: Regularly check and clean or replace the fuel filter to ensure a clean fuel supply.
Regular Maintenance
- Spark Plug Care: Inspect and clean or replace the spark plug periodically.
- Air Filter Cleaning: Keep the air filter clean to ensure proper airflow.
- Carburetor Adjustment: Periodically check and adjust carburetor settings if you’re comfortable doing so, or have a professional do it during routine servicing.
Frequently Asked Questions (FAQ)
Q1: How long should I let a flooded Stihl chainsaw sit?
A: If you suspect your chainsaw is flooded, it’s best to let it sit for at least 15-30 minutes with the spark plug removed. This allows excess fuel to evaporate from the cylinder and carburetor.
Q2: Can I start a Stihl chainsaw without the spark plug?
A: No, you cannot start a chainsaw without the spark plug. However, you remove the spark plug temporarily to help clear a flooded engine.
Q3: What is the difference between a flooded engine and a cold engine that won’t start?
A: A flooded engine has too much fuel in the cylinder. A cold engine that won’t start might be due to lack of fuel, insufficient spark, or the choke not being engaged correctly for cold conditions.
Q4: My Stihl chainsaw still smells like gas after I tried to start it. What should I do?
A: If it still smells strongly of gas after attempting to start and clearing the plug, the carburetor might be leaking or delivering too much fuel. You may need to inspect the carburetor or have it serviced.
Q5: Do I need to drain the fuel to unflood a chainsaw?
A: Typically, no. The methods described above focus on clearing excess fuel from the combustion chamber and allowing evaporation. Draining the fuel is usually a last resort or part of a deeper carburetor cleaning process.
By following these expert tips on how to start a flooded Stihl chainsaw, you can efficiently clear a flooded chainsaw and resume your work. Remember that proper maintenance and correct operating procedures are key to preventing these issues in the first place. If you’re consistently facing Stihl starting issues flooded, it’s worth having your chainsaw inspected by a qualified technician.