Master the Art of Chainsaw Ignition Coil Testing: Step-by-Step Guide

A chainsaw that won’t start can be a frustrating experience, especially when you need it for a job. One of the most common culprits for a non-starting chainsaw is a faulty ignition coil. The ignition coil is responsible for generating the high voltage spark that ignites the fuel-air mixture in the engine cylinder. If the coil is damaged or defective, the spark will be weak or absent, preventing the engine from starting.

This guide will explain how to test chainsaw ignition coil to diagnose the problem and determine if it’s the culprit behind your chainsaw’s woes. We’ll cover the essential tools, safety precautions, and step-by-step instructions to help you get your chainsaw back in working order.

Understanding the Ignition Coil

The ignition coil is a vital component in a chainsaw’s ignition system. It’s a small, cylindrical device with a primary and secondary winding. When the engine is cranked, the primary winding receives a low-voltage signal from the ignition module. This signal induces a high-voltage current in the secondary winding, which is then directed to the spark plug. The spark plug then ignites the fuel-air mixture, driving the engine.

Common Signs of a Faulty Ignition Coil

Before diving into the testing process, it’s important to identify the signs of a faulty ignition coil. Here are some common symptoms:

• No spark at the spark plug: This is the most obvious sign of a faulty ignition coil. You can check for spark by removing the spark plug and grounding it to the engine block. Then, crank the engine and observe if there’s a spark.
• Weak spark: A weak spark may not be enough to ignite the fuel-air mixture reliably, leading to inconsistent starting or engine misfires.
• Engine won’t start: A completely dead ignition coil will prevent the engine from starting altogether.
• Engine dies randomly: If the ignition coil is intermittently failing, the engine may start but then die unexpectedly.

Safety Precautions

Before working on your chainsaw, it’s crucial to prioritize safety. Here are some essential precautions to follow:

• Disconnect the spark plug: This prevents accidental starting while working on the ignition system.
• Wear safety glasses: Protect your eyes from sparks and debris.
• Work in a well-ventilated area: Gasoline fumes are flammable and can be dangerous.
• Use a non-conductive surface: Avoid working on metal surfaces to prevent accidental electrical shocks.

Tools Needed to Test Chainsaw Ignition Coil

To test your chainsaw ignition coil, you’ll need the following tools:

• Multimeter: A multimeter is essential for measuring voltage and resistance.
• Spark plug wrench: Used to remove and install the spark plug.
• Wire cutters or a wire stripper: For stripping the wires leading to the ignition coil.
• Test light: A test light is a simple tool to check for continuity.

How to Test Chainsaw Ignition Coil: Step-by-Step Guide

Now, let’s get into the actual testing process:

1. Disconnect the spark plug: Use the spark plug wrench to remove the spark plug from the cylinder head.
2. Inspect the spark plug: Check the spark plug for signs of wear, damage, or carbon buildup. If the spark plug is faulty, replace it with a new one.
3. Test for spark: Connect the spark plug wire to the spark plug. Hold the spark plug against a grounded metal surface (like the engine block) and crank the engine. Observe if there’s a spark. If there’s no spark, proceed to the next step.
4. Test the ignition coil with a multimeter:

• Measure the resistance of the primary winding: Disconnect the spark plug wire from the ignition coil. Locate the primary winding terminals, usually marked “P” or “+/-“. Connect the multimeter to the terminals and measure the resistance. The resistance should be within the manufacturer’s specifications for your particular chainsaw model.
• Measure the resistance of the secondary winding: Disconnect the wire from the spark plug. Locate the secondary winding terminals, usually marked “S” or “HV”. Connect the multimeter to the terminals and measure the resistance. The resistance should also fall within the manufacturer’s specifications.

5. Test the ignition coil with a test light:

• Continuity test: Connect one lead of the test light to the positive terminal of the ignition coil and the other lead to a ground (like the engine block). Turn the ignition switch to the “on” position. The test light should illuminate.
• Voltage test: Disconnect the wire from the spark plug. Connect one lead of the test light to the spark plug wire and the other lead to a ground. Crank the engine. The test light should illuminate brightly, indicating a strong spark.

6. Evaluate the results: If the ignition coil fails any of the tests, it’s likely faulty and needs to be replaced. If the coil passes all tests, the problem might lie elsewhere in the ignition system.

Troubleshooting Tips

• Check the ignition module: If the ignition coil tests good, the problem might be with the ignition module. The ignition module controls the timing and duration of the spark. A faulty module can cause a weak or intermittent spark.
• Inspect the wiring: Inspect the wiring leading to the ignition coil and spark plug for any damage, loose connections, or corrosion.
• Check the fuel system: Ensure the fuel tank is full, the fuel lines are clear, and the fuel filter is clean.
• Clean the carburetor: A dirty carburetor can cause starting problems. Clean the carburetor thoroughly and adjust the idle and air mixture screws.

The Final Word: Replacing Your Ignition Coil

If you’ve determined that your chainsaw ignition coil is faulty, it’s time to replace it. You can find replacement coils at most chainsaw parts retailers or online.

Remember to always consult your chainsaw’s owner’s manual for specific instructions on replacing the ignition coil. The process typically involves disconnecting the old coil, removing any mounting screws, and installing the new coil in the same position.

Quick Answers to Your FAQs

Q: What is the average life expectancy of a chainsaw ignition coil?

A: The lifespan of a chainsaw ignition coil can vary depending on usage, maintenance, and environmental conditions. However, a well-maintained coil can last for several years.

Q: Can I repair a faulty ignition coil?

A: It’s generally not recommended to attempt to repair a faulty ignition coil. The internal windings are delicate and difficult to access. It’s more cost-effective and safer to replace the coil entirely.

Q: How can I prevent ignition coil problems?

A: You can extend the life of your ignition coil by:

• Using high-quality fuel: Avoid using fuel that’s contaminated or stale.
• Keeping the engine clean: Regular cleaning and maintenance will prevent dirt and debris from accumulating on the ignition system.
• Storing the chainsaw properly: Store your chainsaw in a dry, cool place when not in use.

Q: What are some other reasons why my chainsaw might not start?

A: Besides a faulty ignition coil, other common reasons for a chainsaw not starting include:

• Empty fuel tank: Ensure the fuel tank is full.
• Dead battery: If your chainsaw has an electric start, check the battery.
• Clogged fuel filter: A clogged fuel filter restricts fuel flow to the engine.
• Flooded engine: If you’ve tried to start the chainsaw multiple times, it might be flooded with fuel.
• Dirty spark plug: A dirty spark plug can prevent a spark from forming.

By following the steps and tips outlined in this guide, you can effectively test your chainsaw ignition coil and determine if it’s the culprit behind your starting problems. Remember to prioritize safety and consult your chainsaw manual for specific instructions. With a little troubleshooting, you can get your chainsaw running smoothly again!