Exclusive Tips: How to Test Chainsaw Ignition Coil with Multimeter for Beginners

A chainsaw’s ignition coil is a vital component that transforms low-voltage battery power into high-voltage spark, igniting the fuel-air mixture and powering your chainsaw. When your chainsaw refuses to start or experiences intermittent problems, a faulty ignition coil is often the culprit. Knowing how to test chainsaw ignition coil with a multimeter is a valuable skill for any chainsaw owner, enabling you to diagnose problems and potentially save money on costly repairs.

Understanding the Ignition Coil and Its Function

The ignition coil is a transformer that increases the voltage of the battery’s output, creating the high voltage spark necessary to ignite the fuel. It consists of two windings: a primary winding and a secondary winding. The primary winding is connected to the battery and ignition module, while the secondary winding is connected to the spark plug. When the ignition module sends a signal, current flows through the primary winding, creating a magnetic field. This magnetic field collapses and induces a high voltage current in the secondary winding, which is then sent to the spark plug, igniting the fuel.

Why Test the Ignition Coil?

A faulty ignition coil can manifest in various ways, leading to frustrating chainsaw problems. Here are some common symptoms:

• Engine won’t start: A completely dead ignition coil will prevent any spark from reaching the spark plug, making starting impossible.
• Intermittent starting: If the ignition coil is partially faulty, it might only work intermittently, causing the chainsaw to start sometimes but not others.
• Engine misfires or runs roughly: A weak spark from a faulty ignition coil can lead to misfires and inconsistent engine performance.
• Backfiring: A faulty ignition coil can cause backfires, which can be dangerous and damaging to the engine.

Tools and Materials You’ll Need

Before you begin testing your chainsaw ignition coil, gather the following tools:

• Multimeter: A digital multimeter is essential for measuring resistance and voltage.
• Screwdriver: A screwdriver appropriate for the screws on your chainsaw’s ignition coil cover.
• Safety Glasses: Protect your eyes from any potential debris or sparks.
• Gloves: Use gloves to protect your hands from sharp edges or potential electrical shocks.

Step-by-Step Guide to Test Chainsaw Ignition Coil with Multimeter

Now, let’s walk through the process of testing your chainsaw ignition coil with a multimeter:

1. Disconnect the Spark Plug Wire:

• Locate the spark plug wire connected to the ignition coil and carefully disconnect it.
• Ensure the spark plug wire is secured away from the engine to prevent accidental contact.

2. Set the Multimeter to Resistance Mode:

• Select the “Ohms” (Ω) setting on your multimeter.
• Most multimeters have a range of resistance settings; choose an appropriate range for testing ignition coils (usually in the kilohms or megohms range).

3. Test the Primary Winding:

• Connect the multimeter probes to the two terminals on the primary winding of the ignition coil.
• The terminals on the primary winding are usually smaller than those on the secondary winding.
• Note the resistance reading on the multimeter. The resistance reading should be within the manufacturer’s specifications for your specific ignition coil. If the reading is significantly different, the primary winding is likely faulty.

4. Test the Secondary Winding:

• Connect the multimeter probes to the terminals on the secondary winding of the ignition coil.
• The terminals on the secondary winding are usually larger than those on the primary winding.
• Note the resistance reading on the multimeter. The resistance reading should be within the manufacturer’s specifications for your specific ignition coil. If the reading is significantly different, the secondary winding is likely faulty.

5. Check for Continuity:

• With the multimeter still set to resistance mode, touch the probes together.
• The multimeter should display a zero reading, indicating continuity.
• This step helps ensure your multimeter is functioning correctly.

6. Test the Spark Plug:

• While you’re at it, it’s a good idea to test the spark plug as well.
• Connect the spark plug wire to the spark plug, then ground the spark plug to the engine block.
• With the engine cranked, observe the spark.
• A healthy spark should be bright blue and consistent. If the spark is weak or nonexistent, the spark plug might be faulty.

Interpreting the Test Results

Here’s how to interpret the test results:

• Primary Winding: If the resistance reading is significantly different from the manufacturer’s specifications, the primary winding is likely faulty.
• Secondary Winding: If the resistance reading is significantly different from the manufacturer’s specifications, the secondary winding is likely faulty.
• Continuity Test: If the multimeter does not display a zero reading when the probes are touched together, your multimeter might be malfunctioning.
• Spark Plug Test: If the spark is weak or nonexistent, the spark plug might be faulty.

Replacing a Faulty Ignition Coil

If your test results indicate a faulty ignition coil, you’ll need to replace it. Here’s a general guide:

• Purchase a new ignition coil: Ensure the new ignition coil is compatible with your chainsaw model.
• Disconnect the battery: Disconnecting the battery is always a good safety practice before working on electrical components.
• Remove the old ignition coil: Remove the screws securing the ignition coil cover and carefully remove the old coil.
• Install the new ignition coil: Install the new ignition coil in the same location as the old one. Secure it with the screws.
• Reconnect the spark plug wire: Connect the spark plug wire to the new ignition coil.
• Reconnect the battery: Reconnect the battery and start the chainsaw.

Troubleshooting Tips

• Double-check your connections: Make sure all connections are secure and free of corrosion.
• Check the ignition module: If the ignition coil tests good but the chainsaw still won’t start, the ignition module might be faulty.
• Consider other components: If you’ve ruled out the ignition coil, spark plug, and ignition module, consider other potential issues, such as a clogged fuel filter or a faulty carburetor.

Final Thoughts: Beyond the Spark

Testing your chainsaw ignition coil with a multimeter is a valuable skill for any chainsaw owner. By understanding the basics of the ignition system and following the steps outlined above, you can troubleshoot common problems and potentially save money on repairs. Remember, safety is paramount when working with power tools. Always wear appropriate safety gear, disconnect the battery before working on electrical components, and consult your chainsaw’s owner’s manual for specific instructions.

What You Need to Know

Q1: Can I use a regular multimeter to test a chainsaw ignition coil?

A: Yes, a standard digital multimeter can be used to test a chainsaw ignition coil. It’s important to choose a multimeter with appropriate resistance ranges for testing ignition coils, typically in the kilohms or megohms range.

Q2: What are the common signs of a faulty ignition coil?

A: Common signs of a faulty ignition coil include:

• Engine won’t start
• Intermittent starting
• Engine misfires or runs roughly
• Backfiring

Q3: How do I know if I need to replace the ignition coil?

A: If the resistance readings on the primary and secondary windings are significantly different from the manufacturer’s specifications, the ignition coil is likely faulty and should be replaced.

Q4: Can I repair a faulty ignition coil?

A: No, ignition coils are typically not repairable. If the coil is faulty, it needs to be replaced.

Q5: What should I do if my chainsaw still won’t start after replacing the ignition coil?

A: If your chainsaw still won’t start after replacing the ignition coil, you should consider other potential issues, such as a faulty spark plug, a clogged fuel filter, or a malfunctioning ignition module.