The frustration of a sputtering, refusing-to-start lawn mower is a tale as old as time. And more often than not, the culprit behind this mechanical misery is a faulty ignition coil. This crucial component sparks the fuel-air mixture in your mower’s engine, bringing it to life. But when the coil goes kaput, your mowing dreams go up in smoke.
This article is your guide to understanding and troubleshooting ignition coils in lawn mowers. We’ll explore how to identify a faulty coil, provide step-by-step instructions for checking it, and offer insights into common coil problems and their solutions.
Understanding the Ignition Coil
The ignition coil is a transformer that converts low-voltage battery power into high-voltage current. This high voltage ignites the fuel-air mixture in the engine’s combustion chamber, causing a controlled explosion that propels the mower’s blades.
How to Check Your Lawn Mower Coil
Before you get your hands dirty, ensure your mower is disconnected from any power source and cool to the touch. Here’s a comprehensive guide to checking your ignition coil:
1. Visual Inspection: The First Line of Defense
Start by visually inspecting the ignition coil for any obvious signs of damage. Look for:
- Cracked or broken insulation: This indicates a damaged coil that’s likely not functioning correctly.
- Corrosion: Corrosion on the coil’s terminals can interrupt the flow of electricity.
- Loose connections: A loose wire or connection can cause intermittent sparking or a complete lack of ignition.
- Burn marks: Burnt areas on the coil can indicate overheating and potential failure.
If you spot any of these issues, it’s a strong indication that your coil needs to be replaced.
2. The Spark Test: A Direct Check
The spark test is the gold standard for diagnosing a faulty ignition coil. It’s a straightforward process that allows you to directly observe the spark produced by the coil.
Here’s what you’ll need:
- Spark plug tester: This tool features a wire with a spring-loaded terminal at one end and a built-in ground wire.
- Safety glasses: Always protect your eyes when working with electricity.
Steps for the spark test:
- Disconnect the spark plug wire: Locate the spark plug wire leading to the coil and carefully disconnect it.
- Attach the spark plug tester: Connect the spark plug tester to the spark plug wire. Make sure the ground wire of the tester is secured to a good ground on the mower’s frame.
- Turn the engine over: Have a helper crank the mower engine while you observe the spark plug tester.
- Check for a spark: A strong, blue spark should jump between the tester’s terminal and the spark plug wire.
Interpreting the results:
- Strong blue spark: Your ignition coil is working correctly.
- Weak or no spark: Indicates a problem with the coil.
Important Note: If you have a spark but the engine still isn’t running, the problem likely lies with the spark plug itself, the fuel system, or a faulty connection.
3. Resistance Check: The Electrical Approach
If you have access to a multimeter, you can perform a resistance check on the ignition coil for a more in-depth diagnosis. This test involves measuring the resistance of the coil’s primary and secondary windings.
3.1 Measuring Resistance: A Deeper Dive
What you’ll need:
- Multimeter: Choose a multimeter with a resistance setting.
- Owner’s manual: Your mower’s manual will specify the resistance values for your specific model’s ignition coil.
Steps for the resistance check:
- Locate the coil terminals: Most ignition coils have two or more terminals. These are typically labeled “Positive” or “+” and “Negative” or “-.”
- Set the multimeter to resistance mode: Select the resistance setting on your multimeter.
- Test the primary winding: Connect the multimeter probes to the coil’s “+” and “-” terminals. Note the resistance value displayed on the multimeter.
- Test the secondary winding: Disconnect the spark plug wire and connect the multimeter probes to the wire’s terminal and the other coil terminal. Note the resistance value.
3.2 Interpreting the Results: Comparing to Specs
Compare the measured resistance values to the specifications in your owner’s manual. If the values fall within the acceptable range, the coil is likely in good working order. However, if the measured resistance is significantly different from the specified range, the coil may be faulty.
Important Note: Different mower models may have different coil resistance specifications. Always consult your owner’s manual for accurate values.
Troubleshooting Common Ignition Coil Issues
While testing the ignition coil is a crucial step in diagnosing your lawn mower woes, it’s essential to understand the common issues that can arise with these components.
4.1 Understanding Common Coil Issues: A Breakdown
- Coil failure: The most common issue is coil failure, which can be caused by overheating, electrical shorts, or simply wear and tear.
- Intermittent sparking: A coil with a cracked insulation or loose connection might produce an intermittent spark, leading to a sputtering engine.
- No spark: A complete lack of spark is a strong indicator of a faulty coil.
5. Repairing a Faulty Ignition Coil: When Replacement is Needed
If your visual inspection, spark test, or resistance check reveals a faulty ignition coil, you’ll need to replace it.
5.1 Replacing the Ignition Coil: A Step-by-Step Guide
- Disconnect the battery: Always disconnect the battery from your mower before working on electrical components.
- Locate the ignition coil: Identify the coil’s location, usually on the engine block near the spark plug.
- Disconnect wires: Carefully disconnect all the wires connected to the coil. Take note of where each wire goes for reconnection.
- Remove the coil: Use a wrench to remove the bolts or screws securing the coil to the engine.
- Install the new coil: Position the new coil in its original location and secure it using the mounting bolts or screws.
- Reconnect the wires: Connect the wires back to the new coil, ensuring they’re securely attached.
- Reconnect the battery: Reattach the battery terminals.
- Test the engine: Start your mower to ensure the new coil is functioning correctly.
6. Maintaining a Healthy Ignition Coil: Preventing Future Problems
Regular maintenance can help prolong the life of your lawn mower’s ignition coil and prevent future problems:
- Keep it clean: Dust and debris can accumulate on the coil, leading to overheating and potential failure. Clean the coil regularly with a dry cloth or brush.
- Check for loose connections: Periodically inspect the wires connected to the coil for loose connections. Tighten any loose wires to ensure a proper electrical connection.
- Avoid overheating: Avoid running the mower for extended periods in extreme temperatures, which can lead to coil overheating.
Conclusion: Empowered to Troubleshoot
Diagnosing and troubleshooting a faulty ignition coil can be a daunting task, but armed with this comprehensive guide, you are now equipped to tackle this common lawn mower problem head-on. Remember, always prioritize safety by disconnecting the battery and wearing safety glasses. By performing a visual inspection, a spark test, or a resistance check, you’ll be able to determine if your ignition coil is the culprit. And with the right tools and a little know-how, you can confidently replace a faulty coil and get your mower back in tip-top shape for your next mowing adventure.
FAQ
What is a lawn mower coil and what does it do?
The ignition coil is a vital component of your lawnmower’s ignition system. It’s responsible for transforming the low-voltage current from your battery into a high-voltage current that sparks the spark plug, igniting the fuel-air mixture in the engine cylinder. Without a properly functioning ignition coil, your lawnmower won’t start or run properly.
The ignition coil works by using a magnetic field to generate a high-voltage current. When the ignition switch is turned on, the battery sends a low-voltage current to the coil. This current creates a magnetic field around the coil’s primary winding. When the ignition system sends a signal to the coil, the magnetic field collapses, generating a high-voltage pulse that travels to the spark plug, creating the spark that ignites the fuel.
How do I know if my lawn mower coil is bad?
There are several signs that your lawn mower coil might be going bad. The most common symptom is a lack of spark at the spark plug. This can manifest as difficulty starting the mower, inconsistent running, or the mower simply not starting at all. Additionally, you might notice the engine backfiring or sputtering, or a burning smell emanating from the ignition system.
It’s important to note that these symptoms could also be caused by other issues, such as a faulty spark plug, wiring problems, or a bad ignition switch. However, if you’ve ruled out these other possibilities, a bad ignition coil is a likely culprit.
What tools do I need to check my lawn mower coil?
To check your lawn mower coil, you’ll need a few basic tools that are commonly found in most toolboxes. A multimeter is essential for testing the coil’s resistance and voltage output. You’ll also need a screwdriver to access the coil and a pair of wire cutters or pliers to disconnect any wires connected to the coil.
You can usually find these tools at your local hardware store or auto parts store. If you’re not familiar with using a multimeter, it’s best to consult a repair manual or watch a tutorial video before attempting to test your coil.
How do I check my lawn mower coil?
Testing your lawn mower coil involves a series of steps using a multimeter. First, you’ll need to disconnect the coil from the ignition system and then use the multimeter to check its resistance. The resistance should fall within a specific range as specified in your lawn mower’s manual.
Next, you’ll need to connect the multimeter to the coil’s primary and secondary windings and test its voltage output. The coil should produce a high-voltage pulse when the ignition system sends a signal. If the coil fails either of these tests, it’s likely faulty and needs to be replaced.
How do I replace my lawn mower coil?
Replacing a lawn mower coil is a relatively simple process that can be done by most homeowners with basic mechanical skills. First, you’ll need to disconnect the coil from the ignition system. This involves removing any wires connected to the coil, which are usually held in place by terminal clamps or screws.
Once the coil is disconnected, you can remove it from its mounting bracket and install the new coil in its place. Make sure to connect the wires to the new coil in the same order as they were on the old coil. After installing the new coil, reconnect the wires and test the ignition system to ensure the new coil is functioning properly.
What are some common mistakes people make when replacing a lawn mower coil?
One common mistake is failing to disconnect the battery before working on the ignition system. This can lead to electrical shocks or damage to the ignition system. It’s crucial to always disconnect the battery before working on any electrical components in your lawnmower.
Another common mistake is misconnecting the wires to the new coil. This can lead to the coil not functioning properly or even damaging the ignition system. Always double-check that the wires are connected in the correct order before starting the engine.
What safety precautions should I take when working with a lawn mower coil?
When working with a lawn mower coil, it’s important to prioritize safety and take appropriate precautions. Always disconnect the battery before working on the ignition system. This will prevent electrical shocks and ensure your safety.
Wear safety glasses to protect your eyes from flying debris or sparks. It’s also a good idea to wear gloves to protect your hands from cuts or burns. If you’re not comfortable working with electrical components, it’s best to consult a qualified mechanic for assistance.