Are you tired of your lawn mower sputtering and refusing to start? A faulty ignition coil is a common culprit for these woes. But before you rush out to buy a replacement, there’s a simple way to diagnose the problem: test the coil yourself with a multimeter! This article will guide you through the process, step-by-step, so you can determine if your coil needs replacing or if the issue lies elsewhere.
In this comprehensive guide, we’ll explore the function of the ignition coil, learn how to use a multimeter for coil testing, and walk you through the actual testing process. We’ll also cover essential safety precautions and provide troubleshooting tips for common issues.
Understanding the Ignition Coil
The ignition coil is a crucial component in your lawn mower’s ignition system. It’s responsible for transforming the low-voltage electricity from the battery into a high-voltage spark that ignites the fuel-air mixture in the engine’s combustion chamber. When the coil malfunctions, the spark is either weak or nonexistent, leading to engine problems like starting difficulties, misfires, and lack of power.
How to Test a Lawn Mower Ignition Coil with a Multimeter
Testing a lawn mower ignition coil with a multimeter is a straightforward process that can be performed by anyone with basic mechanical skills. You’ll need a few things:
- A digital multimeter: This essential tool allows you to measure voltage, resistance, and continuity, crucial for diagnosing electrical components.
- A set of spark plug wires: These are required to connect the multimeter to the ignition coil.
- Safety glasses: Protect your eyes from potential sparks.
- Gloves: Provide insulation and protection.
Before you begin, always disconnect the battery to prevent electrical shock.
Step 1: Identify the Ignition Coil
Locate the ignition coil on your lawn mower. It’s typically a cylindrical or rectangular component attached to the engine block, with one or more wires connected to it.
Step 2: Disconnect the Spark Plug Wires
Remove the spark plug wires from the coil and the spark plugs. This ensures that no electricity flows through the circuit while you’re testing.
Step 3: Set the Multimeter to Resistance Mode
Set your multimeter to the “ohms” (Ω) setting. This mode allows you to measure the electrical resistance within the coil.
Step 4: Test the Primary Winding
- Connect the multimeter probes to the primary terminals of the coil. These are usually labeled “primary” or “low voltage” on the coil itself.
- Take a reading from the multimeter. A healthy ignition coil will show a resistance reading between 0.5 and 5 ohms.
- If the reading is significantly higher than 5 ohms, or if you get an “open” or “OL” reading, the primary winding is likely faulty.
Step 5: Test the Secondary Winding
- Connect the multimeter probes to the secondary terminals of the coil. These are usually labeled “secondary” or “high voltage.”
- Take a reading from the multimeter. A healthy ignition coil will show a resistance reading between 5,000 and 20,000 ohms.
- If the reading is significantly lower than 5,000 ohms, or if you get an “open” or “OL” reading, the secondary winding is likely faulty.
Troubleshooting Common Coil Issues
If you find that your ignition coil is faulty, there are a few common issues to consider:
1. Worn or Damaged Wires
Inspect the spark plug wires for any signs of wear, cracks, or loose connections. Replace any damaged wires, as they can cause a weak or intermittent spark.
2. Faulty Spark Plugs
Examine the spark plugs for signs of wear, fouling, or corrosion. If they are worn or damaged, replace them with new ones.
3. Ignition System Problems
If the coil tests good, the problem might be elsewhere in the ignition system. A faulty ignition switch, ignition module, or wiring can all lead to engine starting issues.
4. Fuel System Issues
Ensure that the fuel system is working correctly. Check the fuel lines, fuel filter, and carburetor for any obstructions or leaks.
Safety Precautions:
- Always disconnect the battery before working on the ignition system.
- Use caution when working with electrical components.
- Wear safety glasses and gloves to protect yourself from sparks and potential shocks.
Conclusion
Testing your lawn mower’s ignition coil with a multimeter is a simple yet effective way to diagnose starting problems. By following the steps outlined in this guide, you can determine if the coil needs replacing or if the issue lies elsewhere. Remember to prioritize safety and always disconnect the battery before working on any electrical components. With a little bit of knowledge and effort, you can get your lawn mower running smoothly again in no time!
FAQ
1. What is a lawn mower coil, and why does it matter?
A lawn mower coil is a vital component in your mower’s ignition system. It transforms the low voltage from the battery into a high voltage spark that ignites the fuel mixture in the engine’s combustion chamber. Without a functional coil, your lawn mower won’t start because it cannot generate the necessary spark to ignite the fuel. The coil acts as a transformer, taking the 12 volts from your battery and boosting it to thousands of volts, allowing the spark plugs to ignite the fuel-air mixture in your mower’s cylinder.
2. How do I know if my lawn mower coil is dead?
If your lawn mower fails to start, there are several signs that point towards a dead coil. The most obvious is that the engine simply won’t fire up. Another indicator is a lack of sparks at the spark plug. If you see sparks but they are weak or intermittent, this could also indicate a failing coil. Lastly, if you hear a clicking sound from the starter but no engine running, the issue might lie with the coil not providing sufficient voltage to ignite the fuel.
3. What tools do I need to test my lawn mower coil?
To test your lawn mower coil, you need a multimeter. A multimeter is a versatile tool that can measure voltage, current, and resistance, making it invaluable for diagnosing electrical problems. You will also need a set of spark plug wires, a screwdriver to remove the spark plug, and a pair of safety glasses to protect your eyes from any accidental sparks.
4. How do I test the lawn mower coil with a multimeter?
Testing a lawn mower coil with a multimeter involves a few simple steps. First, unplug the spark plug wire from the coil. Then, set your multimeter to the resistance setting (usually ohms). Connect one multimeter probe to the coil’s positive terminal and the other to the negative terminal. Read the resistance reading on the multimeter. If the resistance falls within the manufacturer’s specified range, the coil is likely functional. If the reading is out of range or the multimeter displays “OL” (overload), then the coil is faulty.
5. What should the resistance readings be for a lawn mower coil?
The resistance reading for a lawn mower coil varies depending on the make and model of your mower. It’s essential to consult your lawn mower’s owner’s manual or refer to online resources for the specific resistance range for your model. A common range for lawn mower coils is between 5,000 and 10,000 ohms.
6. Can I replace the lawn mower coil myself?
Replacing a lawn mower coil is a relatively straightforward task that most DIY enthusiasts can handle. It usually involves removing the old coil, disconnecting the spark plug wire, and attaching the new coil to the spark plug wire. However, it’s crucial to ensure the new coil is compatible with your specific lawn mower model.
7. How do I choose the right replacement coil for my lawn mower?
Choosing the right replacement coil is crucial for ensuring proper functionality and safety. The easiest way to find the correct coil is by looking at the original coil’s markings. They will often include a part number, which you can use to find an identical replacement online or at your local auto parts store. You can also refer to your lawn mower’s owner’s manual or contact the manufacturer for assistance in selecting the appropriate coil for your mower.