The warm sun is shining, the birds are chirping, and you’re ready to tackle your lawn. You pull the cord on your trusty lawnmower, and it roars to life… for a moment. Then, with a sputter and a cough, it dies. Frustration sets in. Why did it start and then die? What’s wrong with your lawnmower? This article will dive into the common culprits behind a lawnmower’s sudden death, offering clear explanations and practical solutions to get you back to mowing in no time.
In short, a lawnmower that starts and then dies is often experiencing an issue with fuel delivery, ignition, or air intake. This could be due to a clogged carburetor, a faulty spark plug, or even a simple lack of fuel.
Fuel Problems: The Most Common Culprit
The most frequent reason for a lawnmower starting and dying is a problem with the fuel system. Here’s what to check:
1. Empty Fuel Tank
This may sound obvious, but a completely empty tank is a common reason for a sudden shut-off. Simply refill your fuel tank and try starting the mower again.
2. Old or Bad Fuel
Gasoline degrades over time, becoming gummy and unusable. If your lawnmower hasn’t been used in several months, the fuel might be stale.
Here’s how to tell if you have bad fuel:
- Appearance: Fresh gasoline is clear, while old fuel may appear cloudy or have a reddish hue.
- Smell: Fresh gasoline has a strong, pungent smell. Old fuel will have a more stale or varnish-like odor.
Solution:
- Drain and replace: The best solution is to drain the old fuel from the tank and carburetor (if possible), and refill with fresh, high-octane gasoline.
- Fuel stabilizer: To prevent future fuel problems, consider adding a fuel stabilizer to your tank. It helps prevent fuel degradation and keeps your mower running smoothly.
3. Clogged Carburetor
The carburetor is responsible for mixing fuel and air before sending it to the engine. If the carburetor becomes clogged with dirt, debris, or varnish, it can disrupt the fuel flow and cause the engine to stall.
Signs of a clogged carburetor:
- Difficulty starting the engine
- Engine sputters or dies when accelerating
- Black smoke from the exhaust
Solution:
- Cleaning: You can try cleaning the carburetor with a carburetor cleaner kit. This involves disassembling the carburetor, removing any debris, and spraying it with cleaner.
- Replacement: If the carburetor is severely clogged or damaged, replacement may be necessary. Consult your owner’s manual or a local mechanic for guidance.
Ignition Problems: Making Sure the Spark Flies
The ignition system, which includes the spark plug, spark plug wire, and ignition coil, delivers the electrical spark that ignites the fuel-air mixture in the combustion chamber. Issues in this system can also lead to a lawnmower starting and then dying.
1. Faulty Spark Plug
The spark plug is the key component of the ignition system. Over time, spark plugs can wear out, become fouled with carbon deposits, or even crack. A faulty spark plug can result in a weak spark, misfires, or no spark at all.
Signs of a faulty spark plug:
- Difficulty starting the engine
- Engine runs rough or misfires
- Black smoke from the exhaust
Solution:
- Replacement: Replace the spark plug with a new one of the correct type for your lawnmower. Consult your owner’s manual or a local mechanic for the correct spark plug specification.
- Gap check: If the spark plug is still relatively new, check the spark plug gap. The gap should be within the manufacturer’s specifications. You can adjust the gap with a spark plug gap tool.
2. Spark Plug Wire Problems
The spark plug wire transmits the electrical spark from the ignition coil to the spark plug. A damaged, loose, or corroded wire can disrupt the spark and cause engine problems.
Signs of a faulty spark plug wire:
- Engine runs intermittently or misfires
- Difficulty starting the engine
Solution:
- Inspection: Visually inspect the spark plug wire for signs of damage, cracks, or corrosion.
- Replacement: If the wire is damaged, replace it with a new one. Ensure it is securely connected to both the spark plug and the ignition coil.
3. Faulty Ignition Coil
The ignition coil generates the high-voltage electrical current needed for the spark plug. A faulty ignition coil can produce a weak or no spark, resulting in engine issues.
Signs of a faulty ignition coil:
- Difficulty starting the engine
- Engine runs rough or misfires
- No spark at the spark plug
Solution:
- Testing: Test the ignition coil using a multimeter to confirm it is producing the required voltage.
- Replacement: If the ignition coil is faulty, replace it with a new one.
Air Intake Problems: A Matter of Breathing
The lawnmower engine needs a steady supply of fresh air to mix with the fuel and ignite properly. A blocked or restricted air intake can lead to a lean fuel mixture, causing engine problems.
1. Clogged Air Filter
The air filter protects the engine from dust, debris, and other contaminants. A clogged air filter restricts airflow to the engine, causing it to run poorly or stall.
Signs of a clogged air filter:
- Difficulty starting the engine
- Engine runs rough or loses power
- Reduced fuel efficiency
Solution:
- Cleaning: If the air filter is reusable, clean it with soap and water or compressed air. Allow it to dry completely before reinstalling it.
- Replacement: If the air filter is disposable, replace it with a new one.
2. Obstructed Air Intake
Sometimes, debris or other objects can block the air intake, preventing air from reaching the engine.
Solution:
- Inspection: Carefully inspect the air intake for any obstructions.
- Removal: Remove any debris or objects that are blocking the air intake.
Other Potential Causes
While fuel, ignition, and air intake problems are the most common culprits, other factors can also contribute to a lawnmower starting and then dying.
- **Choke: ** If the choke is left in the on position, it can restrict airflow to the engine, causing it to stall. Make sure the choke is off when the engine is warmed up.
- **Battery: ** A weak battery can prevent the starter from turning the engine over, even if the engine itself is in good working order. Check the battery terminals for corrosion and try jump starting the mower with a good battery.
- **Starter problems: ** If the starter motor is damaged or worn out, it may not be able to crank the engine fast enough to start. This requires a professional mechanic to diagnose and repair.
- **Fuel lines: ** Clogged or cracked fuel lines can prevent fuel from reaching the carburetor.
- **Governor: ** A faulty governor, which controls engine speed, can cause the engine to stall.
- **Valve timing: ** Incorrect valve timing can disrupt the engine’s combustion cycle.
Troubleshooting Tips
Here are some tips for troubleshooting a lawnmower that starts and then dies:
- Start with the simple things: Before diving into more complex repairs, check the basics like the fuel tank, air filter, and spark plug.
- Use a multimeter: A multimeter is a handy tool for testing electrical components like the ignition coil and spark plug.
- Consult your owner’s manual: Your lawnmower’s owner’s manual contains valuable information about troubleshooting common problems and maintaining your mower.
- Seek professional help: If you’re unable to diagnose or fix the problem yourself, consult a qualified mechanic.
Get Back to Mowing!
A lawnmower that starts and then dies can be frustrating, but by understanding the common causes and following these troubleshooting steps, you can get your mower running smoothly again. Remember to perform regular maintenance on your lawnmower, such as changing the spark plug and air filter, to prevent these issues in the future. With a little care and attention, you can keep your lawnmower in top condition and enjoy a beautifully manicured lawn.
FAQs
Why does my lawnmower start then die?
This is a common problem that can be caused by a variety of factors. The most likely culprits are a lack of fuel, a clogged air filter, a dirty spark plug, or a faulty carburetor. By systematically checking each of these components, you can usually pinpoint the problem and get your lawnmower running again.
You can start by checking the fuel tank to make sure it’s full and that the fuel line is clear. Then, check the air filter for dirt and debris. If it’s dirty, clean or replace it. Next, inspect the spark plug for corrosion or buildup. If necessary, clean or replace the spark plug. Finally, examine the carburetor for dirt and debris. If it’s dirty, clean it thoroughly.
How do I check the fuel tank and fuel line?
To check the fuel tank, simply look at the fuel gauge or visually inspect the tank to see if it’s full. To check the fuel line, you’ll need to disconnect it from the carburetor and then blow through it to see if there’s any blockage.
If you find that the fuel tank is empty, simply add more fuel. If you find that the fuel line is blocked, you can try cleaning it with a wire brush or replacing it with a new one.
What should I do if the air filter is dirty?
If the air filter is dirty, you’ll need to clean it or replace it. To clean the air filter, you can use a vacuum cleaner with a brush attachment to remove any dirt or debris. If the air filter is too dirty to clean, you’ll need to replace it with a new one.
It’s important to keep the air filter clean because it helps to prevent dirt and debris from entering the engine, which can cause it to overheat and damage the engine.
How do I check and clean the spark plug?
To check the spark plug, you’ll need to remove it from the engine. Once it’s removed, you can inspect it for any signs of corrosion or buildup. If you see any corrosion or buildup, you can clean it with a wire brush or replace it with a new one.
A dirty or faulty spark plug can prevent the engine from starting or running properly. If you’re having trouble starting your lawnmower, it’s always a good idea to check the spark plug.
What if the carburetor is dirty?
If the carburetor is dirty, you’ll need to clean it. This can be a bit of a complex task, but it’s important to do it carefully and thoroughly. You’ll need to remove the carburetor from the engine and then disassemble it. Once it’s disassembled, you can clean the various parts using a carburetor cleaner and a soft brush.
A dirty carburetor can prevent the engine from getting the proper amount of fuel, which can cause it to start and die. If you’re having trouble starting your lawnmower, it’s always a good idea to check the carburetor.
What are some other possible causes of a lawnmower starting then dying?
In addition to the common causes mentioned above, there are a few other possibilities that you should consider. These include:
- A faulty ignition coil: The ignition coil is responsible for sending a spark to the spark plug. If the ignition coil is faulty, it can prevent the engine from starting or running properly.
- A bad fuel pump: The fuel pump is responsible for transferring fuel from the tank to the carburetor. If the fuel pump is faulty, it can prevent the engine from getting enough fuel.
- A clogged fuel filter: The fuel filter helps to prevent dirt and debris from entering the engine. If the fuel filter is clogged, it can prevent the engine from getting enough fuel.
If you’ve ruled out the common causes and are still having trouble, you may need to take your lawnmower to a qualified mechanic for diagnosis and repair.
When should I consider taking my lawnmower to a mechanic?
If you’ve tried all of the troubleshooting steps mentioned above and your lawnmower is still starting then dying, it’s time to take it to a qualified mechanic. A mechanic will be able to diagnose the problem and make the necessary repairs.
It’s always best to err on the side of caution and have a mechanic take a look at your lawnmower if you’re not comfortable working on it yourself. This will help to ensure that the problem is fixed correctly and that your lawnmower is safe to use.