The frustration of a sputtering, refusing-to-start lawn mower is a feeling every homeowner knows too well. While a myriad of potential culprits can cause such lawnmower woes, one often overlooked component is the ignition coil. This unsung hero plays a crucial role in converting the battery’s low voltage into the high voltage spark needed to ignite the fuel-air mixture in your engine. This article will delve into the telltale signs of a faulty ignition coil, equip you with the knowledge to perform a basic check, and guide you through troubleshooting and replacement steps.
Understanding the Ignition Coil’s Role
The ignition coil acts like a transformer, stepping up the low voltage from your battery to the high voltage needed to create a spark at the spark plug. When the engine cranks, the ignition system sends a signal to the coil, energizing it. This energization creates a magnetic field, which in turn induces a high voltage current through the secondary winding of the coil. This high voltage current travels through the spark plug wire to the spark plug, generating a spark that ignites the fuel-air mixture in the combustion chamber.
Signs of a Faulty Ignition Coil
Several symptoms can indicate a failing ignition coil:
- The Engine Won’t Start or Runs Intermittently: If the ignition coil isn’t providing the necessary high voltage spark, your engine might struggle to start or run consistently.
- Backfiring: A faulty coil can lead to misfires, causing a backfiring sound from the engine.
- Engine Stalling: If the ignition coil malfunctions during operation, the engine might stall suddenly.
- Spark Plug Not Sparking: If you remove the spark plug and test it while cranking the engine, you should see a bright blue spark. If there’s no spark, the ignition coil might be the culprit.
How to Check an Ignition Coil: A Basic Guide
While a comprehensive check of the ignition coil requires specialized tools and a deeper understanding of electrical circuits, you can perform a basic visual inspection and test the continuity of the coil using a multimeter.
Visual Inspection:
- Locate the Ignition Coil: The ignition coil is typically found near the spark plug, often mounted on the engine block or near the cylinder head. It may have a distinctive rectangular or cylindrical shape with wires connected to it.
- Check for Damage: Inspect the ignition coil for any visible signs of damage, such as cracks, burns, or corrosion. If you notice any damage, it’s likely a sign of a faulty coil.
Continuity Test with a Multimeter:
- Disconnect the Ignition Coil: Disconnect the wires leading to the ignition coil.
- Set Multimeter to Resistance Mode: Set your multimeter to the ohms (Ω) setting.
- Test Continuity: Connect the multimeter probes to the terminals on the ignition coil. Refer to your lawnmower’s manual or consult an online resource for the correct terminal locations.
- Interpret Readings: A multimeter reading within the specified range (usually between 0.5 and 5 ohms) indicates the coil is working properly. A reading outside this range might point to an issue with the coil.
Important Note:
- Safety First: Always disconnect the battery before working on any electrical components, including the ignition coil.
- Consult Your Manual: Before proceeding with any troubleshooting or repairs, refer to your lawnmower’s manual for specific instructions and safety guidelines.
Replacing a Faulty Ignition Coil
If your initial checks indicate a faulty ignition coil, replacing it is usually the best course of action. Here’s a general outline:
- Purchase the Correct Replacement: Identify the make and model of your lawnmower and locate the correct replacement coil from a reputable parts supplier. Ensure that the replacement coil is compatible with your specific engine model.
- Disconnect the Battery: Before starting the replacement process, disconnect the battery terminals to prevent electrical shocks.
- Remove the Old Coil: Carefully disconnect the wires connected to the old coil. You may need to loosen a mounting bolt or clip to remove it entirely.
- Install the New Coil: Connect the wires from the new ignition coil to the appropriate terminals. Secure the coil to its mounting location using the appropriate fasteners.
- Reconnect the Battery: After ensuring all connections are secure, reconnect the battery terminals.
Troubleshooting Tips
If replacing the ignition coil doesn’t resolve the issue, consider these additional troubleshooting steps:
- Inspect the Spark Plug: Make sure the spark plug is properly gapped and in good condition. A worn-out or fouled spark plug can also hinder ignition.
- Check the Spark Plug Wire: Inspect the spark plug wire for cracks, damage, or loose connections. A faulty wire can disrupt the flow of high voltage current to the spark plug.
- Examine the Ignition System: The ignition system includes components like the ignition module, distributor (if applicable), and wiring. Any issues with these components could also contribute to ignition problems.
Conclusion
A faulty ignition coil can leave you with a frustratingly inoperable lawnmower. By understanding the role of the ignition coil, learning how to check it, and troubleshooting effectively, you can tackle this issue head-on and restore your lawnmower to its mowing glory. Remember to prioritize safety, consult your lawnmower’s manual, and seek professional help if you encounter difficulties beyond your expertise.
Frequently Asked Questions
Q1: What is an ignition coil and what does it do?
An ignition coil is a vital component in your lawn mower’s ignition system. It’s essentially a transformer that boosts the low voltage from your battery (typically 12 volts) into a much higher voltage (up to 20,000 volts). This high voltage is then delivered to the spark plugs, creating the spark that ignites the fuel-air mixture in the engine’s cylinders. Without a functioning ignition coil, your lawn mower won’t start.
Q2: What are the signs of a faulty ignition coil?
Several signs can indicate a faulty ignition coil. The most common is a failure to start, or the engine only running intermittently. You might also notice misfires, backfiring, or a decrease in engine power. If you suspect a faulty coil, check for visible damage, like cracks or burns, and use a multimeter to test the coil’s resistance.
Q3: Why does my ignition coil fail?
Several factors can contribute to an ignition coil failing. Age is a major factor, as coils can wear out over time. Extreme temperatures, vibration, and moisture can also damage them. Additionally, a faulty spark plug or other ignition system components can overload the coil, leading to its failure.
Q4: How do I test an ignition coil?
Testing an ignition coil involves using a multimeter to measure its resistance. Different coils have specific resistance ranges, which you can find in your lawn mower’s manual. Disconnect the wires from the coil and measure the resistance between the primary and secondary terminals. If the readings are outside the acceptable range, it’s likely the coil has failed.
Q5: How do I replace a faulty ignition coil?
Replacing a faulty ignition coil is a relatively straightforward process. First, disconnect the battery to prevent electrical shock. Then, locate the coil, usually near the spark plugs. Disconnect the wires and remove the old coil. Carefully install the new coil, ensuring the wires are properly connected, and reconnect the battery.
Q6: Can I repair a faulty ignition coil?
Unfortunately, repairing a faulty ignition coil is rarely possible. Most coils are sealed units, making internal repairs impractical. If the coil is showing signs of damage, it’s best to replace it entirely.
Q7: How can I prevent future ignition coil failures?
While you can’t completely eliminate the risk of an ignition coil failing, you can take steps to prolong its lifespan. Regularly inspect the coil for signs of damage, ensure the spark plugs are in good condition, and maintain proper engine temperatures. Using high-quality components and avoiding harsh conditions can also help.