A flooded lawnmower is a common frustration for homeowners. It happens when too much fuel enters the engine’s cylinder, preventing the spark plug from igniting the air-fuel mixture. Understanding the causes, symptoms, and remedies can save you time, money, and a lot of frustration. Let’s dive deep into the world of flooded lawnmowers.
Understanding Lawnmower Flooding
Lawnmower engines, typically small four-stroke or two-stroke engines, rely on a precise air-fuel mixture for combustion. When this balance is disrupted by an excess of fuel, the engine becomes flooded. Several factors can contribute to this problem.
Common Causes of Flooding
Over-priming is perhaps the most frequent culprit. The primer bulb is designed to inject a small amount of fuel into the carburetor to aid starting, especially in cold weather. Pushing it too many times can saturate the engine.
Tilting the lawnmower excessively, especially when the fuel tank is full, can also lead to flooding. Fuel can leak into the carburetor and cylinder, overwhelming the engine.
A faulty carburetor can be a major source of flooding. A stuck float or a malfunctioning needle valve can allow fuel to continuously flow into the engine, regardless of whether it’s running or not.
Leaving the choke on for too long can also flood the engine. The choke restricts airflow, enriching the fuel mixture for starting. Once the engine is warm, the choke should be turned off to allow a proper air-fuel ratio.
Identifying a Flooded Lawnmower
Recognizing the symptoms of a flooded lawnmower is crucial for prompt action. The most obvious sign is the engine’s inability to start after repeated attempts.
You might also notice a strong smell of gasoline emanating from the engine or the exhaust. This indicates that excess fuel is present.
The spark plug might be wet with gasoline when you remove it. This is a definitive sign of flooding.
In some cases, you might hear a gurgling sound from the engine when you try to start it. This is the sound of the engine struggling to turn over due to the excessive fuel.
The Unflooding Process: A Step-by-Step Guide
The time it takes to unflood a lawnmower can vary depending on the severity of the flooding and the specific method employed. However, most methods take between 15 minutes to a few hours. Patience is key, as rushing the process can sometimes worsen the problem.
The Simple Wait-It-Out Method
The simplest approach is often the most effective, though it requires patience. Simply wait for the excess fuel to evaporate. This can take anywhere from 15 minutes to an hour, depending on the ambient temperature and humidity.
Remove the spark plug wire to prevent accidental starting while waiting. This is a crucial safety precaution.
After waiting, try starting the lawnmower without using the primer or choke. This allows the engine to draw in air and clear out any remaining fuel.
Removing the Spark Plug
Removing the spark plug and pulling the starter cord several times can help to expel the excess fuel from the cylinder. This method is generally faster than waiting.
First, disconnect the spark plug wire. Then, use a spark plug wrench to carefully remove the spark plug.
Inspect the spark plug for signs of fouling or damage. If it’s excessively dirty or damaged, it might need to be cleaned or replaced.
With the spark plug removed, pull the starter cord several times to allow the fuel to escape.
Reinstall the spark plug, reconnect the spark plug wire, and try starting the lawnmower without using the primer or choke.
Using the Choke and Throttle
This method involves manipulating the choke and throttle to create a lean air-fuel mixture that can help to clear the flood.
Set the throttle to the highest position. This allows maximum airflow into the engine.
Turn the choke off (open position). This further reduces the amount of fuel entering the engine.
Pull the starter cord several times. The increased airflow should help to clear the excess fuel.
If the engine starts, gradually adjust the throttle to a normal operating speed.
Draining the Carburetor
If the flooding is severe or the other methods are not working, draining the carburetor may be necessary.
Locate the drain screw on the carburetor. This is usually a small screw located at the bottom of the carburetor bowl.
Place a container underneath the carburetor to catch the draining fuel.
Loosen the drain screw to allow the fuel to drain out.
Once the fuel has drained completely, tighten the drain screw.
Try starting the lawnmower without using the primer or choke.
Using Starting Fluid (with Caution)
Starting fluid can be used as a last resort to help ignite the fuel mixture, but it should be used with extreme caution.
Spray a small amount of starting fluid into the air intake.
Try starting the lawnmower immediately.
Avoid using excessive amounts of starting fluid, as this can damage the engine.
Cleaning or Replacing the Spark Plug
A fouled spark plug can prevent the engine from starting even after the excess fuel has been cleared.
Remove the spark plug and inspect it. If it’s covered in carbon deposits or fuel, it needs to be cleaned or replaced.
Clean the spark plug using a wire brush or spark plug cleaner.
If the spark plug is damaged or excessively worn, replace it with a new one.
Ensure that the spark plug gap is set to the correct specification before reinstalling it.
Preventing Future Flooding
Preventing flooding in the first place is far easier than dealing with the aftermath. Several practices can significantly reduce the risk of this issue.
Proper Priming Techniques
Avoid over-priming the engine. Consult the owner’s manual for the recommended number of primer pumps. Generally, one to three pumps are sufficient, especially in warmer weather.
In cold weather, you may need to prime the engine slightly more, but avoid excessive priming.
Correct Choke Usage
Use the choke only when necessary, such as during cold starts. Once the engine is running smoothly, turn the choke off.
Avoid leaving the choke on for extended periods, as this can lead to flooding.
Proper Storage and Handling
Store the lawnmower on a level surface to prevent fuel from leaking into the carburetor.
When transporting the lawnmower, ensure that the fuel tank is empty or properly sealed to prevent spills.
Regular Maintenance
Regularly inspect and clean the air filter. A dirty air filter can restrict airflow and cause the engine to run rich, increasing the risk of flooding.
Check the spark plug regularly and replace it as needed.
Have the carburetor professionally cleaned or rebuilt if you suspect it’s malfunctioning.
Fuel Stabilizer
Using a fuel stabilizer in the gasoline, especially when storing the lawnmower for extended periods, can help prevent fuel degradation and carburetor issues. Fuel stabilizer prevents the fuel from breaking down and forming gummy deposits that can clog the carburetor.
Troubleshooting Persistent Flooding Problems
If your lawnmower continues to flood despite your best efforts, there may be an underlying mechanical issue that needs to be addressed.
Carburetor Issues
A faulty carburetor is a common cause of persistent flooding. The float valve may be stuck open, allowing fuel to continuously flow into the engine. The jets within the carburetor could also be clogged or damaged.
A professional carburetor cleaning or rebuild may be necessary to resolve this issue.
Float Issues
The float inside the carburetor controls the fuel level. If the float is damaged, punctured, or improperly adjusted, it can cause the carburetor to flood.
Inspect the float for any signs of damage. If it’s damaged, replace it.
Adjust the float level according to the manufacturer’s specifications.
Needle Valve Issues
The needle valve regulates the flow of fuel into the carburetor. If it’s worn, damaged, or contaminated, it can leak and cause flooding.
Inspect the needle valve for any signs of wear or damage. Replace it if necessary.
Fuel Line Issues
A damaged or leaking fuel line can also contribute to flooding.
Inspect the fuel lines for any cracks, leaks, or damage. Replace any damaged fuel lines.
Tools and Materials You Might Need
Having the right tools and materials on hand can make the unflooding process much easier.
- Spark plug wrench: For removing and installing the spark plug.
- Screwdrivers: For various adjustments and repairs.
- Pliers: For gripping and manipulating small parts.
- Starting fluid (optional): Use with extreme caution.
- Fuel stabilizer: To prevent future fuel degradation.
- Clean cloths or rags: For cleaning up spills and wiping parts.
- Container: To catch draining fuel.
- Wire brush or spark plug cleaner: For cleaning the spark plug.
- New spark plug (optional): For replacement if needed.
Conclusion
Dealing with a flooded lawnmower can be frustrating, but by understanding the causes, recognizing the symptoms, and following the appropriate troubleshooting steps, you can often resolve the issue quickly and efficiently. Remember to prioritize safety by disconnecting the spark plug wire before performing any maintenance. Preventive measures, such as proper priming techniques and regular maintenance, can significantly reduce the risk of future flooding. While the exact time to unflood a lawnmower varies, patience and a systematic approach are key to getting your lawnmower back up and running smoothly. When in doubt, consulting a qualified lawnmower repair technician is always a wise choice.
FAQ 1: What does it mean for a lawnmower to be flooded?
Flooding in a lawnmower refers to the engine receiving too much fuel relative to the amount of air. This excess fuel saturates the spark plug, preventing it from igniting the air-fuel mixture necessary for combustion. Consequently, the engine fails to start, and attempts to start it further exacerbate the problem by introducing more fuel into the cylinder.
Essentially, the engine is choked with unburnt fuel. This can be caused by several factors, including repeatedly priming the engine, tilting the mower excessively, or issues with the carburetor. Understanding the cause of the flooding is crucial for preventing future occurrences and ensuring the lawnmower operates efficiently.
FAQ 2: How can I identify if my lawnmower is flooded?
The most common symptom of a flooded lawnmower is the inability to start after multiple attempts. You may hear the engine turning over, but it won’t ignite. Often, you will smell a strong odor of gasoline emanating from the engine or the exhaust area.
Another indicator is a wet spark plug. If you remove the spark plug and it appears damp or saturated with fuel, it’s a clear sign that the engine is flooded. Avoid continuously trying to start the mower in this condition, as it will only worsen the flooding and potentially damage the engine.
FAQ 3: What is the simplest method to unflood a lawnmower?
The simplest method to unflood a lawnmower often involves letting the engine sit for a period. This allows the excess fuel to evaporate naturally from the cylinder. Remove the spark plug wire for safety. Then, leave the mower untouched for approximately 15 to 30 minutes.
After waiting, reattach the spark plug wire. Try starting the mower without priming or using the choke. If it starts, gradually increase the throttle. If it still doesn’t start, proceed to more involved methods, such as removing the spark plug.
FAQ 4: How does removing the spark plug help unflood a lawnmower?
Removing the spark plug allows direct ventilation to the engine cylinder. This open passage facilitates the evaporation of excess fuel that has accumulated. By removing the plug, you are providing a pathway for the gasoline fumes to escape, effectively drying out the combustion chamber.
After removing the spark plug, pull the starter cord several times. This action further helps to expel any remaining fuel from the cylinder. Before reinserting the spark plug, clean it with a wire brush or a dry cloth to ensure it is free from fuel residue.
FAQ 5: What role does the carburetor play in lawnmower flooding, and how can it be addressed?
The carburetor is responsible for mixing air and fuel in the correct proportions for combustion. If the carburetor malfunctions, it can deliver too much fuel, leading to flooding. A common issue is a stuck float valve, which allows fuel to continuously flow into the carburetor bowl, even when the engine doesn’t need it.
Addressing carburetor issues typically involves cleaning or rebuilding the carburetor. Cleaning can be done with carburetor cleaner spray. Rebuilding requires replacing worn parts like the float valve and gaskets. If you’re not comfortable performing these tasks, it’s best to consult a qualified mechanic.
FAQ 6: How does the choke lever affect lawnmower flooding?
The choke lever restricts airflow into the carburetor, enriching the fuel mixture for starting a cold engine. While essential for cold starts, excessive or improper use of the choke can easily lead to flooding. Leaving the choke engaged for too long after the engine has warmed up delivers an overly rich mixture, causing excess fuel to accumulate in the cylinder.
To prevent flooding related to the choke, use it only when necessary for initial starting, and disengage it as soon as the engine runs smoothly. If you suspect the engine is flooded due to the choke, ensure the choke lever is in the “off” or “run” position before attempting to restart the mower.
FAQ 7: Are there preventative measures to avoid flooding my lawnmower?
Yes, several preventative measures can significantly reduce the risk of flooding your lawnmower. Avoid over-priming the engine. Follow the manufacturer’s recommendations for the number of primes required. Also, avoid tilting the mower excessively, especially when it contains fuel, as this can cause fuel to leak into the cylinder.
Regular maintenance of your lawnmower is crucial. Ensure the air filter is clean and the spark plug is in good condition. Periodically check the carburetor for any signs of leaks or malfunctions. By adhering to these practices, you can minimize the chances of flooding and prolong the lifespan of your lawnmower.