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How to test the ignition coil on a leaf blower: a step-by-step guide

The ignition coil also called ignition armature, is a crucial functional tool in the power system of a leaf blower, especially the one powered by gas. It is the part that starts the device and may fail to run when there is a problem. For instance, if your blower has been functioning well but stops and cannot power on or start all of a sudden when you pull the cord, then there are chances that your ignition coil has a  problem. There may be many causes of ignition failure, but the first step is always to test the coil.

To test the ignition coil on a leaf blower you should follow these steps:

  1. Open the motor
  2. Detach the parts
  3. Disconnect the wire that runs to the spark plug
  4. Remove the ignition coil
  5. Test with an ohmmeter or a multimeter
  6. Start the test
  7. interpret your observation
  8. Decide what the fix will be
  9. Reconnect the ignition coil

Testing the ignition coil of a leaf blower is therefore vital, and it is something that you should be able to do on our own. This article will give the step by step guide into doing just that. However, before we go into testing the ignition coil, there are some key things you need to know. The first one is to understand how the ignition coil works.

How an ignition coil of a leaf blower works

An ignition coil is a small component in the engine of a leaf blower. It connects the spark plug with the flywheel that rotates when the leaf blower is turned on through a starter cord. All three components (flywheel, spark plug, and ignition coil) are  found in the engine. The starter is located on the outside part of a leaf blower. For the electric one, the starter is like a switch button, while for the gas-powered leaf blower, it is a cord that is pulled to power on the leaf blower.

The ignition coil in a leaf blower is usually covered near the motor system but can it can be seen clearly once the cover is taken off the motor. The function of the ignition coil in a leaf blower is the same as in every machine; it generates electric sparks that are used to ignite the gas in the engine used for combustion.

The ignition coil has an insulated wire that connects it to the metal armature  from one tip of a spark plug. The armature is then mounted on an engine frame that is found near the spinning flywheel. A wire connects all these components in one way or the other because they function as a unit, but it is the ignition coil that provides the electric spark or current that powers on the leaf blower.

The armature has two coils. When the magnets found along the edges of the flywheel, whiz closer to the coils, electricity is generated. Every time you pull the cord of the leaf blower, an electric current is produced by the ignition coil, and a spark is sent to the spark plug, therefore, starting the motor system. That is on a manual starter leaf blower.

For the electric starter motor, the flywheel is spun by a battery starter instead of pulling a cord. Regardless of the model you are using, the flywheel continues to turn once the leaf blower is powered on. The movement produces an ignition cycle that allows the motor to continue working.

When the leaf blower fails to “catch” when you are trying to start it, there are chances that the ignition coil or the spark plug are not functioning properly. You may not know the part that is not working unless you test the engine. It is mostly the ignition coil.

There are many parts in the motor system of a leaf blower that can cause the ignition problem. However, the most common culprit is the ignition coil. Therefore, this article will show you how to test the ignition coil of a leaf blower through a step by step guide. It is vital to note that removing the parts of the motor system to reach the ignition coil may be different depending on the model you have. The good news is that testing the coil follows the same procedure in all types of leaf blowers.

The process of testing the ignition coil of a leaf blower

There are many ways of testing the ignition coil of a leaf blower. Some older mechanics tend to use the method that involves disconnecting the spark plug wire and holding it against a metal chassis while cracking the engine. If there is a spark, then the ignition coil is not the problem. However, this method is not recommended to home users because of its complexity and the risk of an electric shock. Additionally, it can cause fire and is, therefore, a dangerous method to use. A safer way is to use an ignition coil tester (you can find them here). The recommended steps of testing a leaf blower are as follows:

Step one: open the motor cover

All the elements of starting the engine of the leaf blower are delicately covered near the motor. You need a screwdriver to open the motor cover. Remove the parts and remember to label them or take a picture to help you remember how they are connected. You do not want to be in a situation where you cannot reconnect the parts after you are done testing the ignition coil of the leaf blower. Once you have opened it up, remove the cowling. The cowling is the casing of the motor or engine. Then use the screwdriver to loosen screws around the parts.

Step two: detach the parts

Separate the sparkplug from the other parts. This means getting the plug out of the engine delicately without cutting any wire. Mark the metal chassis of the motor or engine. Disconnect the cable on the spark plug. To disconnect the wire, you can leave the spark plug in its place and only remove the wire. However, it is recommended to remove the entire part for safety.

Step three: test the ignition coil

This is where you will test your wire. This step is the most crucial and requires concentration and precaution. Make sure to hold the insulated part of the wire and not the naked part.

 Hold the wire that you removed from the spark plug against the chassis. At the same time, you should be cracking the engine and checking if the wire produces any spark. If you see flashes of light when the cord meets the chassis, then the coil is working, and you need to find out the problem from other parts of the engine.

If the ignition coil is broken you have to replace it. You can find leaf blower ignition coils here.

A safer way to test the ignition coil

Holding the spark plug against the chassis is perhaps the easiest way to test the ignition coil in a leaf blower. It is however not the safest or most convenient way. In many instances, you may not see the sparks because they are small. That does not mean that the coil is the problem. You may see tiny sparks when the ignition coil is actually not working.

These, along with other concerns, make the second method the most efficient, safest, and popular among home users. The technique involves disconnecting the ignition module and using an ohmmeter to test the coil. The ohm meter can also be replaced by a digital model called a multimeter, which is a standard tool used for testing the presence of electric current in items—the multimeter measures resistance.

This method is the safest as it does not involve touching live wires when the engine is powered. This way can be used on any model of the ignition coil.

Another method is to use an ignition coil tester. You can find one here.

Materials needed:

  • Removal tools: Essential tools for the removal of the ignition coil and loosening the screws and bolts.
  • Multimeter: A digital multimeter (An ohmmeter or multimeter, which is a tool that is used to test the electrical charge in the ignition coil. It is the tool that will show you whether the ignition coil is functioning or not). You can find a good multimeter here.

Step one: get the instructions right

Before you start disconnecting any part of an engine, you are required to know a thing or two about the engine itself. This rule applies to all forms of tools. You will have to research different things, including the specifications of the leaf blower. Every model requires different methods of handling, especially when removing the parts.

You also need to know the type of motor you are dealing with. Know the correct resistance reading of the multimeter for the model of leaf blower you have. The best way of doing this is by contacting your retailer or searching about these specifications online. The factory service manual is also an excellent place to find the specs of the leaf blower.

Step two: disconnect the parts

Use your screwdriver to loosen all the screws and bolts found on the outer casing (cowling) of the motor. Gently remove the cover and set it aside. Depending on the model of the leaf blower, you should be able to see the flywheel and the ignition coil once the cowling is removed. Other models always have some shield parts that must be moved altogether to reach the ignition coil. However, many types do not have this extra layer.

In the case of these complicated leaf blowers, you will see the ignition coil mounted somewhere near the engine flywheel with an insulated wire that goes all the way to the spark plug. That is the wire that connects the coil and the spark plug.

Step three: disconnect the wire that runs to the spark plug

At this stage, you are required to remove the cable that runs to the spark plug from the plug. Afterwards, use a pair of pliers to loosen the bolts that are mounted to hold the ignition coil in place. Removing these involve unscrewing tiny screws around that area. Once you are done, the coil should be freely suspended with nothing holding it tight.

Step four: remove the ignition coil

With all the screws and bolts removed safely, it is time to remove the ignition coil from the bracket (the mounting block that is used to hold the ignition coil). In other models, you will find that the ignition coil is connected to a ground wire. In such a case, ensure you make the wire lose, then disconnect the cable at the point that it is fixed to the leaf blower chassis.

Step five: test with an ohmmeter or a multimeter

You need to find out if your ohm meter is working correctly. The first thing will be connecting it to a source of power and see if the leaf is moving. Be careful when doing this, so that you do not damage the multimeter. Always take note of the resistance indicated and try not to exceed. Once you have noted that it is functioning well, then you can continue.

Step six: start the test

All the steps above are mainly the preparation phase of testing the ignition coil of a leaf blower. That means getting things ready for the primary process. Step six is where you start the actual testing of the ignition coil. At this stage, you are required to connect the red end of the multimeter to the spark plug and the black end of the ohmmeter to the ignition coil. Both ends of the multimeter have a tooth-like structure that will make it easier for you to connect it. 

Once you have connected them properly, place the ignition coil on a flat surface, on a table, or any other work surface you can use. Reset the leaf of the ohmmeter to read 20k ohms. Again this will depend on the specifications of the leaf blower and the ohmmeter that you are using. All of them come with directions of use, so you won’t find it hard if you are using a different model.

Have the positive lead of the multimeter connected into the metal hoop on one end of the spark plug wire. Alternatively, you can find this end of the wire in a socket shape. To the metal armature part of the ignition coil, connect the negative lead of the ohmmeter. Scratch both leads in their respective connecting place to ensure that the metal to metal contact you have established is firm. Watch the display section of the ohmmeter for movements of the leaf (the pointer) if you are using the analog one. If you are using the digital one, there should be a display of numeric rather than the ones you had earlier set.

Step seven: interpret your observation

You have taken the readings (that is if there were any) and noted them down. Now the next thing is to know what it means. If the ohmmeter displayed a reading of “one,” that shows that there was complete resistance. Such an interpretation also shows that there was no connection. Since the link was there, this implies that the ignition coil is not working.  

If the multimeter gives you a reading of “zero,” then it means that there was no resistance at all. That is good news for you because it indicates that your ignition coil is working correctly. However, getting a reading of 0 is not logical. In that case, you will see something between 2.5k to 5k ohms. That’s also an indication that the ignition coil is okay.

Step eight: Decide what the fix will be

The aim of this was to test if the ignition coil is working well or not. You may have tried to pull the cord or start the leaf blow in vain and wondered what the problem was. Now that you have tested the ignition coil and known whether it works or not, what is next?

If the ignition coil turns out to be the problem, then you will need to get a new one and replace it. Before buying a spare part of the leaf blower, ensure that it is compatible. Go for the specs that match your tool. The best way to buy a spare part is by carrying the faulty one to your retailer to get you one that is the same. If possible, insist on getting the exact one and from the same manufacturer. Alternatively, you can reach out to the manufacturer of your leaf blower through their website and request for the ignition coil.

You can find new leaf blower ignition coils here.

Step nine: reconnecting the ignition coil

Having bought a new ignition coil, you will have to connect it before you can use your leaf blower again. Some people can opt for an expert. However, this should not be that hard for you, especially if you have removed the parts on your own and tested the ignition coil.

In the process of removing the parts, it is recommended that you label the elements and, if possible, take a picture. This would help when reconnecting them back. Unless you have a very sharp memory or you are an expert, please do so.

To install the new ignition coil, first, you need to attach the ground wire to the chassis of the leaf blower (that is if your model has a ground wire). Follow it up by connecting the armature end of the ignition coil. Consider the instructions about the gap that should be between the magnet on the flywheel and the armature metal part of the ignition coil. If you are not in a position to get these directives, then you can use a small piece of paper or cardboard to separate the two. Alternatively, you can use a spark plug gapping equipment.

Use the screwdriver to tighten the armature to the engine frame. Remember to use all the screws you removed.

Step ten: finish it up

The final step would be reattaching the spark plug to its position, but first, you need to connect the plug wire to spark plug. With all that done, you can now start your leaf blower and see if it is working. Given that you have followed all these steps diligently, your leaf blower should start and run smoothly.

At this point, you have learnt how to test the ignition coil of a leaf blower. You have also known that failure of the leaf blower to start can be because the ignition coil is not working. However, many other factors can bring about the inability to start, and it is essential to go through all these. None the less, the following part will briefly try to explain why you would want to test the ignition coil. Accordingly, it will explore other problems that might cause the failure of the leaf blower to start.

What is the essence of testing the ignition coil of a leaf blower?

You probably know why you want to test the ignition coil of your leaf blower. But is it always the coil that you ought to check? The answer is no. Testing the ignition coil is one way of finding where the problem lies. That means that other parts can also cause the same problem. And if the test shows that the ignition coil is working correctly, but the leaf blower still does not start, then you should focus on other parts as well. 

Reasons why the spark plus is not working

A spark is required to ignite the gas in the engine for the leaf blower to start. If the ignition coil is faulty, this current will not be produced, and the engine will not start. But again, the coil might produce the spark, but the connecting wire fails to transmit it to the spark plug. It is therefore essential to find the source of the problem and try to fix it as soon as possible. Here are some of the causes:

Faulty Spark Plug

The spark plug can cause the failure of the leaf blower to start if it is destroyed or have carbon deposits on the surface. The metal tip that connects to the motor should be clean to transmit the spark to initiate combustion. If it is not clean, then the motor will not start. In the same way, if the tip has is not well gapped, then the spark produced will not fire into the combustion chamber to light the fuel (gas). Additionally, the spark plug may have worn out, and the strips on its surface failed to connect firmly to the cylinder causing the same problem.

In case of faulty spark plugs, you need to replace the old ones with a new one and you will have your leaf blower blowing once again. A cheaper alternative is cleaning the tip of the spark plug (the metal side); however, this might just be a temporary fix and it is not recommended unless you have no other option.

You can find new sparkplugs here.

● Faulty wires

The wire connecting the parts of the motor system may be broken or connected in the wrong way causing a problem when starting the leaf blower. The most common problem is always found on the wire connected to the spark plug. This is the wire that transmits the current from the ignition coil to the spark plug. Once there is any problem with this wire (or any other wire in the ignition module), there will be the premature grounding of the circuit. When a wire is also loose or when the insulation wears out, and it touches the engine chassis, then the same problem is faced.

The solution to this is checking the connection points to find out where there is a broken wire. Replace the cables that are loose, corroded, or stripped.

Non-functional stop switch

This is not a common problem, but it can also happen. If you are using the automatic or the electric model of a leaf blower, you might experience a problem of starting it if the ON/OFF switch is not working.

What you need to do in this case is to replace the switch with a new one.

Final word

Testing the ignition coil of a leaf blower may be overwhelming, especially for first-timers. However, the step by step guide given in this article should help you go through this process with a lot of ease and at the same time help you discover other problems that might cause the failure of the leaf blower to start. The need to help you identify other issues is brought by the fact that you might find out that the ignition coil of your leaf blower is working correctly, but the leaf blower still fails to start. 

If you follow the steps as described and finds out that your leaf blower is the problem, then you will need to replace it with a better one. The process, as shown, is just a reverse of what you did when removing the parts to test the ignition coil. The critical thing to do is installing a new coil following the guideline provided and the instructions from your retailer. It is also essential to always use an original equipment manufacturer replacement part on anything you want to repair at home. Not only does it gives you an easy time, but it also saves you the headache of returning pieces that do not match or fit well.

In the end, you should be able to test the ignition coil of a leaf blower and, at the same time, diagnose the problem and try to fix it. Good luck.