The smell of fresh-cut grass is a delightful sign of a well-maintained lawn. But what happens when that satisfying hum of your lawnmower turns into a sputtering, coughing mess? The culprit could be a faulty ignition coil, a critical component that helps ignite the spark plug and bring your engine to life.
This article will guide you through the process of testing your lawnmower coil, helping you determine if it’s the source of your lawnmower woes. We’ll cover the basics of how the ignition coil works, explore the common signs of a faulty coil, and walk you through the steps of testing it using a simple multimeter.
Understanding the Ignition Coil: The Spark of Life for Your Lawn Mower
The ignition coil is a small but vital part of your lawnmower’s engine. It transforms the low-voltage electrical current from your battery into a high-voltage spark that ignites the air-fuel mixture in the combustion chamber. This spark is what sets the engine running and keeps it going.
Signs of a Faulty Ignition Coil
Here are some common indicators that your lawnmower coil might be on the fritz:
- Engine Won’t Start: A completely dead coil will prevent the spark plug from firing, making it impossible to start the engine.
- Engine Starts, But Dies Quickly: This suggests the coil might be delivering a weak spark, not enough to keep the engine running.
- Engine Runs Erratically: Sputtering, misfiring, or uneven engine performance can also indicate a faulty coil.
- Spark Plug Shows No Spark: You can visually check for a spark at the spark plug to confirm the coil is faulty.
Essential Tools for Testing Your Lawn Mower Coil
Before you embark on the testing journey, gather the following tools:
- Multimeter: A multimeter is a crucial tool for measuring voltage, current, and resistance. You can find a basic one at any hardware store or online.
- Spark Plug Wrench: This tool is used to remove and replace the spark plug.
- Safety Glasses: Protect your eyes from any potential sparks or debris.
- Gloves: Protect your hands while handling the coil and other parts.
Step-by-Step Guide to Testing Your Lawn Mower Coil
Now, let’s dive into the testing process:
1. Disconnect the Battery: Before working with electrical components, always disconnect the battery terminals to avoid accidental shocks.
2. Locate the Ignition Coil: The ignition coil is typically located near the spark plug and the engine’s head. It might be covered by a metal shield or heat shield.
3. Disconnect the Spark Plug Wire: Using a spark plug wrench, remove the spark plug from its socket and carefully pull out the spark plug wire connected to the coil.
4. Prepare Your Multimeter: Set your multimeter to the “resistance” or “ohm” setting. Consult your multimeter’s manual for specific instructions.
5. Test the Primary Winding:
* Locate the Primary Winding Terminals: Most coils have two primary winding terminals, usually marked “P” or “+” and “G” or “-“.
* Connect the Multimeter Probes: Connect one probe of your multimeter to the “P” terminal and the other probe to the “G” terminal.
* Read the Resistance: The multimeter should show a reading in ohms.
* Compare to Specifications: Refer to your lawnmower’s manual or search for the coil model number online to find the specified resistance range for the primary winding. If the reading falls outside this range, your primary winding is likely faulty.
6. Test the Secondary Winding:
* Locate the Secondary Winding Terminals: These terminals are typically marked “S” or “+” and “C” or “-“.
* Connect the Multimeter Probes: Connect one probe to the “S” terminal and the other to the “C” terminal.
* Read the Resistance: The multimeter should show a higher resistance reading than the primary winding.
* Compare to Specifications: Again, consult your manual or search online to find the specified resistance range for the secondary winding. If the reading falls outside this range, the secondary winding is likely damaged.
7. Troubleshooting and Diagnosis:
- If both the primary and secondary windings show resistance readings within the specified ranges: The issue likely lies elsewhere, such as a faulty spark plug, a bad wire connection, or a problem with the ignition system.
- If one or both windings show an incorrect resistance reading or no reading at all: The ignition coil is most likely faulty and needs replacement.
8. Replace the Ignition Coil: If you’ve confirmed the coil is faulty, replace it with a new one compatible with your lawnmower model.
Tips for Choosing a New Ignition Coil
- Match the Original Coil: Look for a replacement coil that matches the specifications of the original coil in terms of voltage, resistance, and mounting.
- Check for Compatibility: Ensure the new coil is compatible with your specific lawnmower model.
- Consider OEM or Aftermarket Options: Original Equipment Manufacturer (OEM) coils are often more expensive but offer guaranteed compatibility. Aftermarket coils can be more affordable but might require additional research to ensure proper fit.
Maintaining Your Ignition Coil for Optimal Performance
While a faulty coil often indicates a need for replacement, you can take proactive steps to extend its lifespan:
- Keep the Coil Clean and Dry: Regularly clean the coil with a soft brush or compressed air to remove dust and debris.
- Avoid Moisture and Vibration: Protect the coil from excessive moisture and vibration, as these can damage the internal components.
Beyond the Coil: Other Potential Culprits
If you’ve replaced the ignition coil and your lawnmower still isn’t running smoothly, consider these additional potential causes:
- Spark Plug: A worn-out or fouled spark plug can prevent proper ignition.
- Spark Plug Wire: A damaged or corroded spark plug wire can interrupt the spark path.
- Battery: A weak or dead battery can’t supply the necessary voltage for ignition.
- Fuel System: Problems with the fuel pump, carburetor, or fuel lines can hinder fuel delivery.
- Engine Timing: Incorrect engine timing can affect combustion and ignition.
Conclusion: Putting Your Lawn Mower Back in Action
Testing your lawnmower’s ignition coil can save you time and money by helping you identify the source of your engine troubles quickly. Armed with the knowledge and the right tools, you can confidently diagnose and address the issue, ensuring your lawnmower is back in action and ready to conquer the green expanse.
FAQs
What is a lawn mower coil and what does it do?
A lawn mower coil is a vital component of the ignition system that converts low-voltage electricity from the battery into high-voltage electricity. This high voltage is used to create a spark in the spark plug, which ignites the air-fuel mixture in the engine cylinder. Think of it as the ignition switch that starts the engine’s combustion cycle.
Without a properly functioning coil, your lawnmower will not start or run. The coil is responsible for delivering the necessary electrical energy to create a spark, which is essential for combustion. A faulty coil can cause various issues, from weak starting to complete engine failure.
How do I know if my lawn mower coil is dead?
There are several signs that indicate a faulty lawn mower coil. If your lawnmower is having trouble starting, consistently misfiring, or refusing to run, a dead coil could be the culprit. Other signs include backfiring, sputtering, and a lack of power when running.
It’s important to rule out other potential issues before jumping to conclusions. Inspect the spark plug, fuel lines, and air filter to ensure they are in good condition. If you’ve ruled out other possibilities and are still experiencing problems, it’s highly probable that your lawn mower coil has gone kaput.
How do I test my lawn mower coil?
Testing a lawn mower coil requires a basic understanding of electrical circuits and some basic tools. You’ll need a multimeter, a spark plug tester, and a screwdriver. The test involves checking the resistance of the coil’s primary and secondary windings using the multimeter.
If the readings are outside of the manufacturer’s specifications, the coil is likely faulty. You can also use the spark plug tester to check if the coil is producing a spark when the engine is cranked. If there is no spark, the coil is likely the culprit.
What are the different types of lawn mower coils?
Lawn mower coils come in various types, each with specific characteristics and applications. The most common types include:
- Standard coil: This is the most common type of coil used in small engines.
- Electronic ignition coil: These coils are often found in newer lawn mowers and provide more precise ignition timing.
- High-performance coil: Designed for high-performance engines, these coils offer higher voltage and output.
The type of coil you need will depend on your lawnmower’s model and engine type. Consult your owner’s manual or a reputable online source for the correct coil for your machine.
How do I replace a lawn mower coil?
Replacing a lawn mower coil is a relatively simple task that can be done by anyone with basic mechanical skills. You’ll need a new coil that’s compatible with your lawnmower model, a screwdriver, and possibly some wire cutters.
Start by disconnecting the spark plug wire from the old coil and then removing the mounting screws holding the coil in place. Install the new coil in the same location, making sure to connect the spark plug wire properly. Finally, re-attach the mounting screws and test the engine to ensure the new coil is functioning correctly.
Can I repair a lawn mower coil?
Unfortunately, repairing a lawn mower coil is generally not feasible. These coils are typically sealed units, making internal repairs difficult, if not impossible. When a coil fails, it’s usually due to a short circuit, a broken winding, or an internal breakdown.
The cost of repairing a coil often outweighs the cost of a replacement, making a new coil the most practical solution. Focus on finding a reputable replacement coil that is compatible with your specific lawn mower model.
How can I prevent my lawn mower coil from going bad?
While coil failure can happen unexpectedly, there are a few things you can do to prolong the life of your lawn mower coil:
- Regular maintenance: Ensure your lawn mower receives routine maintenance, including cleaning and inspecting the ignition system.
- Use high-quality parts: Choose high-quality spark plugs, wires, and other ignition components to minimize strain on the coil.
- Avoid excessive moisture: Protect your lawn mower from excessive moisture and rain, as it can damage the coil and other electrical components.
By following these tips, you can help prevent coil failure and keep your lawnmower running smoothly.