Testing a magneto coil with a multimeter is an essential part of troubleshooting any issues that you may be having with your bike. In this guide, we will walk you through the process step-by-step so that you can perform this task like a pro. We will also answer some common questions about magneto coils and multimeters, so that you have all the information you need to get started. Let’s get started!
What is a Magneto Coil?
The most common use for a magneto coil is in an ignition system, where it is used to create a spark that ignites the fuel in the engine.
Magneto coils are used in a variety of applications, including generators and solenoids. They are also found in many household appliances, such as hair dryers and vacuum cleaners. [1], [2]
How Does Magneto Coil Work?
When an electric current flows through the coil, it creates a magnetic field. The strength of the magnetic field depends on the number of turns in the coil and the amount of current flowing through it.
The magnetic field can be used to create a force that can either attract or repel other objects. For example, when a magnet is placed near a piece of iron, the iron is attracted to the magnet because of the magnetic force.
Magneto coils can also be used to generate electricity. When a coil is moved through a magnetic field, it produces an electric current. This is how generators and alternators work.
In order for a magneto coil to work properly, it must have two things: a conductor and a magnetic field. The conductor is typically made of copper wire, and the magnetic field is provided by a permanent magnet or an electromagnet. [1], [2]
Symptoms of a Faulty Magneto Coil
Before you get to testing your magneto coil, it is important to know the symptoms of a faulty one. This will help you determine whether or not your coil is actually the problem. Let’s take a look at some of the most common symptoms.
Engine misfires
One of the most common symptoms of a faulty magneto coil is if your engine misfires. If your engine is misfiring, it means that the spark plugs are not firing correctly. This can cause a lot of problems, including decreased fuel efficiency and increased emissions.
Failure to start the engine
Another symptom of a faulty magneto coil is difficulty starting the engine. If your engine is having difficulty starting, it could be because the spark plugs are not firing correctly.
Loss of power
Next common symptom of a faulty magneto coil is a loss of power. This can manifest itself in a number of ways, from your engine running less smoothly to a complete loss of power. If you notice that your engine is losing power, it’s worth checking the magneto coil.
Decreased fuel economy
Decreased fuel economy can also signify a problem with the ignition coil. This is because the coil is not able to generate as much electricity, which means the spark plugs are not getting as much power. As a result, they have to work harder to ignite the fuel, which uses more fuel.
Backfiring
Backfiring is another symptom of a faulty magneto coil. If your engine is backfiring, it’s a good indication that the spark plugs are not working as they should. This can be caused by a number of things, but a faulty magneto coil is one of the most common culprits.
If you’re experiencing this symptom, it’s important to check the other parts of your ignition system as well. This includes the spark plug wires and the distributor cap. If everything else looks fine, then it’s likely that your magneto coil is to blame.
If you notice any of these symptoms, it is likely that your magneto coil is faulty. However, it is important to note that these symptoms can also be caused by other issues. For example, a loss of power could be due to a problem with the spark plugs. Therefore, it is always best to consult a professional before making any repairs. [3]
How to Test a Magneto Coil With a Multimeter
Now that we know the symptoms of a faulty magneto coil, let’s take a look at how to test it. The best way to test a magneto coil is with a multimeter. This is because it can measure the resistance of the coil.
For this project, we will be using a digital multimeter. A digital multimeter is a type of multimeter that uses a digital display. It is more accurate than an analog multimeter and is easier to use.
The most important thing to remember is that you should never test a coil while it’s still installed on the engine. Always disconnect the spark plug wire and remove the coil from the engine before testing.
Detach the flywheel shroud
The first step is to detach the flywheel shroud. The flywheel shroud is a metal cover that protects the flywheel. It is usually held in place by screws or bolts.
Using a screwdriver or wrench, remove the screws or bolts that hold the shroud in place. Then, carefully lift the shroud off of the engine. Be careful not to drop or damage the shroud. Once the shroud is removed, you will be able to see the flywheel and magneto coil.
Remove the casing off the magneto coil
Once you locate the magneto coil, the next step is to remove the casing. The casing is usually made of plastic or metal and it covers the winding of the coil. To remove the casing, unscrew any screws that are holding it in place. Then, carefully pull the casing off of the coil. Be careful not to damage the coil while removing the casing.
Set your multimeter to ohms mode
The next step is to set your multimeter to ohms mode. On a digital multimeter, this is usually done by turning the knob until it says “Ω.” Ohms is the unit of measurement for electrical resistance. Most multimeters have a range of ohms that they can measure. For this project, we will be using the 40,000kΩ range. The correct range matters because it will give you the most accurate reading.
We suggest you turn the auto-ranging feature off when taking resistance measurements from your magneto coil. This feature is not always accurate and it can give you false readings.
Now that you have set your multimeter to the correct mode and range, let’s move on to testing the coil.
Probe your magneto coil
You probably have noticed by now that a multimeter has two probes, or leads. These probes are made of metal and they are used to touch the objects that you want to test. In order to take a resistance measurement from your magneto coil, you will need to touch both probes to the coil at the same time.
We will first begin with a primary coil. Here you shouldn’t have any confusion. Place the red lead of your multimeter on the U-shaped winding of the coil and the black lead on any nearby ground (metal surface). A good ground to use is the engine block. The U-shaped winding is where the current enters the coil.
Now, take a resistance measurement by pressing the “measure” button on your multimeter. You should see a reading in ohms on the display. This is the primary resistance of your magneto coil. Write down this number for later reference.
Next, we will measure the resistance of the secondary coil. The secondary winding is located inside of the primary one. To measure the secondary resistance, place the red probe on the U-winding again and the black probe on the rubber part of the casing.
You have now successfully measured the primary and secondary resistance of your magneto coil!
Interpreting Your Measurements
The primary and secondary resistance readings that you took in the previous section can tell you a lot about your magneto coil. Now it’s time to learn how to interpret these readings and what they mean.
The first thing you need to do is compare your readings to the manufacturer’s specifications. These specifications can be found in your owner’s manual or on the internet. If your readings are within the specified range, then your coil is most likely working correctly. However, if your readings are outside of the specified range, then there might be a problem with your coil.
Generally speaking, you want to get a resistance reading at least between 3K and 15K kilo-ohms. If your readings are lower than these numbers, then it is likely that your coil is not working correctly.
We advise against trying to fix your coil yourself. If you think there might be a problem with your coil, we recommend taking it to a professional mechanic or auto shop. They will have the tools and knowledge necessary to fix or replace your coil. If you have any particular questions, you can contact the manufacturer of your vehicle directly. [1], [2], [4]
FAQ
What are the dangers of malfunctioning ignition coil?
If your ignition coil is not working properly, it can cause a number of problems with your vehicle. Ignition coils are responsible for providing the spark that ignites the air/fuel mixture in the engine, so if they are not functioning correctly, the engine will not run properly.
What is the normal voltage of a magneto coil?
This can vary, but most small engines will have a magneto that produces around 50 volts. Coil can further increase this voltage to 15K V.
How do I know if the magneto coil is damaged?
If your engine is having difficulty starting, or if it’s running inconsistently, there’s a chance that the magneto coil is damaged. Another symptom of a damaged magneto coil is if the engine backfires when starting.
To test whether or not the magneto coil is damaged, you’ll need a multimeter. This way, you can test the coil’s resistance to see if it’s within the normal range.
How do you test a magnetic coil?
To test a magnetic coil, you will need a multimeter. You can use either an analog or digital multimeter. First, set your multimeter to the ohms setting. Then, touch oen of probes of the meter to the leads of the copper wire of the coil and another one to the metal clip. If the meter reading is within 3-15K kiloohms, then your coil is working properly. If it is not, then you will need to replace the coil.
What is the resistance of a magneto coil?
The resistance of a magneto coil can vary depending on the type of coil, but it is generally should be between 3k and 15k kilo ohms.
You can test the resistance of a magneto coil with a multimeter by setting the multimeter to the “resistance” or “ohms” setting and probing the terminals of the coil. If the multimeter reading is outside of this range, then the coil is likely defective and should be replaced.
Useful Video: How To Test a Lawn Mower Magneto Coil
Conclusion
Magneto coils can go bad over time, and when they do, it can be difficult to diagnose the problem. A multimeter is a useful tool that can help you test the coil and determine if it needs to be replaced. With a little knowledge and patience, you can test a magneto coil and get your engine running again in no time. In this article we have covered all the common symptoms of a bad magneto coil and how to test it with a multimeter.
We hope you found this guide helpful! Testing your magneto coil is a great way to diagnose potential ignition problems in your engine. By regularly testing your coil, you can catch problems early and prevent them from becoming bigger, more expensive issues. Thanks for reading!
References
- https://electrouniversity.com/how-to-test-a-magneto-coil-with-a-multimeter/
- https://handtoolsforfun.com/how-do-you-test-a-magneto-coil-with-a-multimeter/
- https://techguy.co.ke/5-symptoms-of-a-bad-or-failing-ignition-coil/
- https://goneoutdoors.com/test-magneto-ignition-coil-7948575.html