The warm weather is here, and you’re itching to get your yard looking its best. But when you pull the cord on your trusty lawnmower, nothing happens. It just sits there, mocking your efforts. Frustrating, isn’t it? Don’t despair! This article will delve into the common reasons why your lawnmower might refuse to start, providing you with a step-by-step troubleshooting guide to get you back to mowing in no time. We’ll cover everything from basic fuel issues to more complex electrical problems, giving you the knowledge you need to diagnose and fix the problem yourself.
In short, a lawnmower that won’t start can be due to a variety of reasons, from simple issues like an empty fuel tank or a clogged air filter to more complex problems such as a faulty spark plug or a broken ignition coil.
Starting with the Basics: Fuel and Spark
The most common reason a lawnmower won’t start is simply because it’s out of fuel. It seems obvious, but you’d be surprised how often this is overlooked.
Fueling Up:
- Check your fuel tank: Is it empty? If so, fill it with fresh gasoline. Make sure to use a fuel stabilizer, especially if you won’t be using the mower for a while.
- Inspect the fuel line: Check for any cracks or kinks in the fuel line. A damaged line can prevent fuel from reaching the carburetor.
- Clean the carburetor: Over time, dirt and debris can build up in the carburetor, clogging the fuel passages. This can prevent the engine from getting enough fuel to start. You can clean the carburetor yourself using a carburetor cleaning kit, or you can take it to a repair shop.
Is There a Spark?
Even if you have fuel, your lawnmower still needs a spark to ignite it. This is where the spark plug comes in.
Checking and Replacing the Spark Plug:
- Remove the spark plug: Use a spark plug socket wrench to remove the spark plug.
- Inspect the spark plug: Look for signs of damage, such as cracks or excessive wear on the electrodes. Also, check the gap between the electrodes. If it’s too wide or too narrow, it can prevent a proper spark.
- Test the spark plug: Hold the spark plug wire to a metal part of the engine with the spark plug grounded. Pull the starter cord a few times. You should see a spark jump across the gap. If you don’t, the spark plug is faulty and needs to be replaced.
- Install a new spark plug: If the old spark plug is damaged or the gap is incorrect, install a new one of the correct type. Make sure to tighten it to the correct torque.
Airflow and Engine Compression
While fuel and spark are essential for combustion, your lawnmower also needs clean air and good compression to run smoothly.
Air Flow Issues:
Checking the Air Filter:
- Location: The air filter is usually located under a cover on the engine, near the carburetor.
- Inspection: Remove the air filter and inspect it for dirt, dust, or debris.
- Cleaning or Replacing: If the air filter is dirty, clean it with soap and water or replace it with a new one.
Compression Problems:
- Causes: Compression problems can be caused by worn piston rings, a damaged cylinder head, or a leaking valve.
- Diagnosing Compression: You can test the engine compression using a compression gauge. This will give you an indication of how well the engine is compressing air. If the compression is low, you’ll need to investigate the cause further.
Electrical System Woes
While the basic fuel and spark issues are common, your lawnmower’s electrical system can also cause it to fail to start.
Battery Problems (For Electric Start Mower):
- Charge Level: If you have an electric start mower, check the battery’s charge. A weak battery might not be able to provide enough power to start the engine. Use a multimeter to check the voltage.
- Battery Connections: Clean any corrosion from the battery terminals and make sure they are firmly connected.
Ignition System Issues:
- Faulty Ignition Coil: This part converts the low voltage from the battery to the high voltage needed for the spark plug. Check for damage, corrosion, or loose connections.
- Broken Ignition Wire: If the ignition wire is damaged or has a loose connection, it can prevent the spark from reaching the spark plug.
- Defective Ignition Switch: The ignition switch controls the flow of electricity to the ignition system. If the switch is faulty, it may not be sending power to the coil or spark plug.
Other Possible Culprits
While the issues outlined above cover the most common causes, there are some other less likely, yet still possible reasons why your lawnmower might not start.
- Flooded Engine: If you’ve been trying to start the mower repeatedly, you may have flooded the engine with fuel. This can happen when the carburetor gets too much fuel. Let the engine sit for a few minutes to let the excess fuel evaporate.
- Stuck Choke: The choke is a device that helps to enrich the fuel mixture for easier starting in cold conditions. If the choke is stuck in the closed position, it can prevent the engine from getting enough air to start. Make sure the choke lever is in the correct position.
- Clogged Fuel Filter: A clogged fuel filter can restrict the flow of fuel to the carburetor.
- Worn Starter Cord: If the starter cord is worn out, it may not be able to pull the engine over fast enough to start it.
A Final Word
Troubleshooting a lawnmower that won’t start can be frustrating, but with a systematic approach and a bit of patience, you can identify and fix the problem. Remember to always use safety precautions when working on your lawnmower, and if you’re unsure about any repair, consult a qualified mechanic. By understanding the basics of how your lawnmower works and following this guide, you can keep your lawn looking pristine all season long.
FAQ
Why won’t my lawnmower start?
This is a common problem that can be caused by a variety of factors. The first thing you should do is check the fuel. Make sure that the tank is full and that the fuel is fresh. If the fuel is old, it may be gummed up and preventing the engine from starting. You should also check the spark plug. A faulty spark plug can prevent the engine from starting. If the spark plug is old or damaged, replace it with a new one.
If you’ve checked the fuel and the spark plug and your lawnmower still won’t start, there may be a problem with the carburetor. The carburetor is responsible for mixing fuel and air. If it’s dirty or clogged, it can prevent the engine from starting. You can try cleaning the carburetor yourself, or you can take it to a mechanic.
What should I do if my lawnmower won’t start after I’ve checked the fuel and spark plug?
If you’ve checked the fuel and spark plug and your lawnmower still won’t start, there may be a problem with the carburetor. The carburetor is responsible for mixing fuel and air. If it’s dirty or clogged, it can prevent the engine from starting. You can try cleaning the carburetor yourself, or you can take it to a mechanic.
If you’re confident in your mechanical skills, you can try cleaning the carburetor yourself. There are many online tutorials that can walk you through the process. If you’re not comfortable doing it yourself, take it to a mechanic.
How do I check if the spark plug is working?
To check if the spark plug is working, you’ll need to remove it from the engine and hold it against the engine block. Then, crank the engine over and see if there’s a spark. If there is, the spark plug is working. If there isn’t, the spark plug is faulty and needs to be replaced.
Make sure to disconnect the spark plug wire before removing the spark plug. This will prevent you from getting shocked. Also, be careful not to drop the spark plug as it can be easily damaged.
What should I do if the fuel is old?
If the fuel in your lawnmower is old, it may be gummed up and preventing the engine from starting. You should drain the old fuel and replace it with fresh fuel. You can also add a fuel stabilizer to the fresh fuel to prevent it from going bad.
If your lawnmower has been sitting for a long time, it’s a good idea to drain the fuel and replace it with fresh fuel even if it doesn’t seem old. This will help to prevent any problems in the future.
Can I use regular gasoline in my lawnmower?
It is not recommended to use regular gasoline in your lawnmower. Lawn mowers require a higher octane fuel, such as 87 or 89 octane. Regular gasoline has a lower octane rating and can cause problems with your lawnmower’s engine.
If you are unsure what type of fuel to use, consult your owner’s manual. The manual will specify the type of fuel that is recommended for your lawnmower.
What should I do if the air filter is dirty?
A dirty air filter can restrict airflow to the engine, making it difficult to start. You should replace the air filter every season, or more often if you use your lawnmower frequently.
If you are unsure how to replace the air filter, consult your owner’s manual. The manual will have instructions on how to remove and replace the air filter.
What if my lawnmower still won’t start after trying all of these things?
If you’ve tried all of these troubleshooting steps and your lawnmower still won’t start, it’s time to take it to a mechanic. There may be a more serious problem with the engine that you’re not able to fix yourself.
A mechanic will be able to diagnose the problem and repair it for you. It’s better to get it fixed sooner rather than later, as a small problem can quickly turn into a big one.