The sweet hum of a freshly tuned lawn mower is music to any homeowner’s ears, promising a well-maintained yard. But what happens when that blissful melody is interrupted by a frustrating sputter and sudden silence? Your lawn mower starts, then abruptly stops, leaving you stranded in a sea of uncut grass. This article will explore the most common culprits behind this annoying issue, providing you with troubleshooting tips to get your mower back in action. We’ll cover everything from fuel problems to ignition issues, and even offer preventative measures to keep your mower running smoothly.
The reasons why your lawn mower starts then stops can range from simple fuel-related problems to more complex ignition issues. A quick check of the fuel system is usually the first step, followed by a look at the spark plug and other ignition components. Let’s dive into the details.
Fuel System Problems
Fuel Shortage or Fuel Quality
The most straightforward reason your mower might be cutting out is simply a lack of fuel. Even if the tank isn’t completely empty, a low fuel level can cause the engine to sputter and die. The fuel pickup tube may not be reaching the bottom of the tank, or there could be a blockage in the fuel line preventing fuel flow.
Another possibility is poor fuel quality. Old or stale gasoline can gum up the carburetor and prevent proper fuel delivery. Ethanol, a common additive in gasoline, attracts moisture and can cause phase separation, leaving behind a watery residue that can clog the fuel system.
To troubleshoot:
- Check the fuel level: Ensure there’s enough fuel in the tank.
- Inspect the fuel lines: Look for any visible cracks, kinks, or blockages.
- Replace old fuel: If you’ve had fuel in the tank for more than 30 days, drain it and replace it with fresh gasoline.
Dirty or Clogged Carburetor
The carburetor is the heart of your mower’s fuel system, responsible for mixing air and fuel in the correct ratio. A dirty or clogged carburetor can lead to a lean fuel mixture, causing the engine to stall.
To troubleshoot:
- Clean the carburetor: You can use a carburetor cleaner kit, or manually clean the carburetor with a small brush and compressed air.
Fuel Filter Issues
A clogged fuel filter can restrict fuel flow to the engine, leading to a lean fuel mixture and stalling.
To troubleshoot:
- Inspect the fuel filter: Check the filter for any visible blockages. Replace the filter if it appears dirty or clogged.
Ignition System Problems
Faulty Spark Plug
The spark plug is responsible for igniting the air-fuel mixture in the combustion chamber. A worn-out, fouled, or corroded spark plug will fail to ignite the fuel properly, causing the engine to sputter and die.
To troubleshoot:
- Inspect the spark plug: Remove the spark plug and inspect it for wear, carbon buildup, or corrosion.
- Replace the spark plug: If the spark plug is damaged or worn, replace it with a new one.
Faulty Ignition Coil
The ignition coil produces the high-voltage spark that ignites the fuel. If the coil is faulty, it won’t generate enough voltage, leading to a weak or no spark.
To troubleshoot:
- Test the ignition coil: You can use a spark tester to check if the coil is producing a spark. If there is no spark, the coil needs to be replaced.
Faulty Ignition Wire
The ignition wire carries the high-voltage spark from the coil to the spark plug. If the wire is damaged or corroded, it can disrupt the spark flow, resulting in a weak or no spark.
To troubleshoot:
- Inspect the ignition wire: Check for any visible damage or corrosion on the wire.
- Replace the ignition wire: If the wire is damaged, replace it with a new one.
Other Potential Causes
Air Filter Clogging
A clogged air filter can restrict airflow to the engine, leading to a lean air-fuel mixture and stalling.
To troubleshoot:
- Inspect the air filter: Check the air filter for dust and debris buildup.
- Clean or replace the air filter: If the air filter is dirty, clean it or replace it with a new one.
Engine Overheating
Overheating can be a common cause for engine stalling. This usually occurs when the engine is working too hard and the cooling system is not able to dissipate the heat.
To troubleshoot:
- Check the cooling system: Make sure the cooling fins are clean and free of debris.
- Add coolant: If the coolant level is low, add more coolant to the radiator.
- Let the engine cool down: If the engine is overheating, let it cool down before restarting it.
Fuel Shutoff Valve
Some lawn mowers have a fuel shut-off valve that can accidentally be turned off, preventing fuel from reaching the engine.
To troubleshoot:
- Check the fuel shut-off valve: Ensure that the valve is open and allowing fuel to flow.
Preventative Maintenance for Your Lawn Mower
Keeping your lawn mower properly maintained can significantly reduce the chances of it starting then stopping. Here are some preventative maintenance tips:
- Change the oil regularly: The engine oil lubricates the moving parts and helps to dissipate heat. Changing the oil at regular intervals will ensure the engine runs smoothly.
- Check and clean the air filter: A clean air filter ensures that the engine gets the proper amount of air for combustion.
- Replace the spark plug: Replace the spark plug every year or every 50 hours of use.
- Clean the carburetor: Clean the carburetor annually or if you experience fuel problems.
- Inspect the fuel lines and filter: Regularly inspect the fuel lines and filter for any signs of damage or blockage.
- Store your lawn mower properly: When not in use, store your lawn mower in a dry, clean place.
Conclusion
A lawn mower that starts then stops can be a frustrating experience, but with a systematic approach to troubleshooting, you can usually identify the problem and get your mower back in working order. Keep in mind that preventative maintenance can go a long way in ensuring your mower runs smoothly and reliably, saving you time and frustration in the long run.
Frequently Asked Questions
Why Does My Lawn Mower Start Then Stop?
Q: Why does my lawn mower start then stop?
A: There are several common reasons why a lawn mower might start and then immediately stop. The most common is a lack of fuel. If the mower hasn’t been used in a while, the fuel may have evaporated or gone bad. Another possibility is a clogged fuel filter or a blocked fuel line. These issues can prevent fuel from reaching the engine, causing it to stall.
Q: What should I check first?
A: The first thing to check is the fuel level. If the tank is empty or close to empty, simply add fuel and try starting the mower again. If you have a fuel filter, you should inspect it for dirt or debris. If the fuel filter is clogged, it will need to be replaced. Finally, examine the fuel line for any kinks or blockages that might be preventing fuel from flowing to the engine.
Q: Could it be a problem with the spark plug?
A: A faulty spark plug can also cause a lawn mower to start and then stop. A spark plug that is worn out or fouled with carbon buildup will not be able to ignite the fuel mixture properly. If you suspect the spark plug is the issue, you should inspect it and replace it if necessary.
Q: What if the spark plug is good?
A: If the spark plug is good, the problem could be with the ignition system. A faulty ignition coil, wire, or switch can prevent the spark plug from receiving a spark. Inspect these components for any signs of damage or corrosion. You may need to replace any damaged components.
Q: What else could be causing the issue?
A: In some cases, the problem might be with the carburetor. A dirty or clogged carburetor can prevent the proper amount of fuel and air from entering the engine. This can lead to a lean fuel mixture, which can cause the engine to stall. A carburetor cleaning or replacement may be necessary.
Q: How can I prevent this from happening again?
A: To prevent your lawn mower from starting and stopping, it’s essential to maintain it regularly. Change the fuel filter regularly, especially if you store your mower for long periods. Inspect the spark plug and replace it as needed. Additionally, cleaning the carburetor periodically can help ensure it’s functioning correctly.
Q: What should I do if I can’t figure out the problem?
A: If you’re unable to diagnose the problem yourself, it’s best to seek professional help. A qualified mechanic can inspect your lawn mower and identify the root cause of the issue. They can then repair or replace any faulty components.