How to Test a Lawn Mower Coil With a Multimeter? (Step by Step)

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Is it time for your lawn to get trimmed like a good boy? Then you must be ready with your lawn mower. If you have not been through lawn days for a long while, you might want to check your lawn mower.

It is natural for a lawn mower to face issues with start-up or a stuck cord if it has not been used for a long time or was stored in wet conditions.

So, suppose it is your former issue, and your lawn mower is not starting. In that case, you need to inspect the conditions leading to start-up failures instead of trying several techniques.

Start-up failures usually occur due to problems with the spark plug, fuel or oil, a stuck pull cord, or the ignition coil. So, you must run proper tests for each one to reach the exact problem.

If your battery, fuel, and pull cord are in good condition and do not pose any hindrance in starting the lawn mower, now you know there is something wrong with the ignition coil. The ignition coil is responsible for generating the voltage that fires the spark plug and hence starts the lawn mower.

Hence, your lawn mower would not start with a damaged ignition coil and might need replacement. But before doing so, you might want to test the ignition coil. The correct method to test an ignition coil is to use an ohmmeter or multimeter to check for continuity.

However, if you are new to using a multimeter for testing the lawn mower coil, do not fret. Here we have provided a step-by-step guide on testing a lawn mower coil with a multimeter to help you fix your lawn mower and get going with your lawn.

Steps to Test a Lawn Mower With a Multimeter

Here are the steps you need to follow to use a multimeter in ohm mode or an ohmmeter to test the ignition coil of your lawn mower.

Step 1: Ignition Coil Removal

Ignition Coil Removal
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To test the ignition coil, you must first remove it from the body of your lawn mower. Hence, you must know where the ignition coil is in the lawn mower. You can find the ignition coil in the lawn mower’s engine attached to the flywheel magnet.

To open the lawn mower’s engine, you must first uncover its plastic wrappings. You can do so with the help of a screwdriver, as all you need is to loosen the screws and proceed further.

You can see the ignition coil as you open the engine cover above the gas tank. You need to deal with the spark plug and the ignition coil. You can notice a high-tension lead in the ignition coil.

You must remove the lead, spark plug, and a kill wire attached to the ignition coil. After you dislodge these components from the lawn mower’s engine, you can easily remove the ignition coil and take it to perform the multimeter test.

Step 2: Time to Perform The Test

Time to Perform The Test
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It is time to hit the arrow on the spot and finally test the ignition coil with a multimeter. Hence, you must keep a multimeter handy along with the engine service manual of the lawn mower you are using.

To perform the test, you must ensure the multimeter is at 20K resistance mode. You must also know the resistance or tolerance value of the ignition coil of your lawn mower.

It is where the service manual of the engine comes into play. You can find a table containing the tolerance value of the ignition coil.

Now, you need to insert the multimeter ends into the ignition coil. While one end goes into the spark plug cap of the high-tension lead, the other end is meant for the coil’s base. Now you can find the resistance value of the ignition coil on the multimeter as per the table you referred to.

The service manual also contains the resistance value for specific points of the ignition coil. You must notice it as you change the positions of the ends of the multimeter on the ignition coil. Next, you need to target the kill wire terminal and the spark plug cap to place the ends of the multimeter.

You can tell if the ignition coil is damaged by noting the resistance readings. If the values are above the range mentioned in the manual, you must change the ignition coil.

Bonus Read: How to Fix a Lawn Mower Whose Cord is Stuck?

Step 3: Getting a New Ignition Coil

Getting a New Ignition Coil
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As you find the ignition coil out of order, you must replace it immediately. Consequently, you need to get a brand-new ignition coil. You must keep a few things in mind while purchasing a new ignition coil and ensure you buy a similar one compared to the damaged one.

You must buy the ignition coil as per the engine model of your lawn mower. If your lawn mower contains two cylinders and you find both the ignition coils to be damaged, you must replace the two of them.

Step 4: Installation of The New Ignition Coil

Installation of The New Ignition Coil
Image Source: liveabout

After you get your brand-new ignition coil ready, you must install it in your lawn mower and watch it running again. You must follow exactly the opposite steps you performed to remove the ignition coil.

You can start by replacing the spark plug from the position you removed it in the first place. You must now reconnect the killer wire to the ignition coil terminal mentioned as the kill wire. Repeat the same for the spark plug cap and screw the ignition coil parts back together.

While doing so, you must maintain a distance of 10 points between the coil and the flywheel’s magnet. You can use a gauge or a simple business card to verify the distance.

Now that you have assembled back the ignition coil, you must cover the engine back and enclose it in plastic coverings. Hence, you are all set with installing the new ignition coil.

Step 5: Testing The New Ignition Coil

Testing The New Ignition Coil
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Now it is time to test if your hard work was successful. Hence, you can try starting your lawn mower with the replaced ignition coil and see if it works now.

Hence, you can get your lawn mower running again like a beast by following the simple steps mentioned above. It is how you can make the best use of a multimeter to test the ignition coil of your lawn mower.

Recommendations Before Test a Lawn Mower Coil

Here are a few recommendations for the things you need to check before testing your lawn mower with a multimeter.

  • Before moving on to the ignition coil, you must check the fuel, fuel filter, and air circulation. Changing the fuel from time to time is good, and not using the old fuel.
  • Next, you must check if the spark plug is in good working condition and if there is no deposition of black soot.
  • Lastly, you must check the amount and quality of oil used in your lawn mower.

Read More: How Much Lime Should You Add to Your Lawn?

FAQ’s to Test a Lawn Mower Coil

Q1. Where is the ignition coil of a lawn mower located?

The ignition coil is located within a metal box connected to the spark plug wire. You can find all these components inside the engine of your lawn mower.

Q2. What equipment do you need to check the ignition coil?

You need a digital multimeter in ohm mode, leather gloves, a service manual for the lawn mower, wrenches, and screwdrivers to perform the multimeter test on the ignition coil.

Q3. What could be the reason behind the breaking of the ignition coil?

Multiple factors can cause ignition coils to break. It could be long-term lawn mower usage or faulty spark plug ignition cables. The latter generates a high voltage and immense heat to melt the insulation and break the ignition coil.

Q4. What multimeters are the best when it comes to maintaining affordability?

Multimeters can be a bit pricey. Hence, you can go for brands that offer affordability besides quality. You can prefer Innova 3340 or the Fluke series for the same.

Q5. How to set up the multimeter before testing the coil?

Before testing the ignition coil, you must set the multimeter to a 20K resistance range. On touching the multimeter’s leads, you must get a reading close to 0. Similarly, when the leads are separated, the reading should be one or infinity.

Conclusion

Lawn mowers can face several issues from time to time, and start-up problems are quite common among them. It could be due to various reasons, but a faulty ignition coil is what creates nuisance most of the time.

So you can test a lawn mower with a multimeter and get a new one by using the recommendations. So, your lawn day is now without any limits.

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