How to test a lawnmower coil with a multimeter, step by step

Want to ensure your lawnmower is always in top shape? Learning to test its coil with a multimeter is vital. Our step-by-step guide makes it easy. Unlock the secret to a perfectly manicured lawn by mastering this skill today!

To test a lawnmower coil with a multimeter, remove the coil, set the multimeter to resistance mode, check the service manual for acceptable range, and touch leads to high-tension lead, kill wire, and base. If readings are out of range, replace the faulty coil, install a new one adequately spaced from the flywheel magnet, reassemble the mower, and test run to confirm function.

Do you know how to test a lawnmower coil with a multimeter? Our step-by-step guide makes it easy. Ready to ensure your lawnmower is always in top shape? Dive in!

DIY Tutorials: Step by step how to test a lawnmower’s ignition coil

The method below explains all the required steps to test the coil with a multimeter and replace it with a new one so that the lawnmower gets up and running again.

● Step 1. Remove the ignition coil from the lawnmower:

• Step 1. Ignition coil location: The ignition coil is inside the lawnmower engine and attached to the lawnmower’s flywheel magnet.
• Step 2. Remove the plastic cover: First of all, remove the plastic covering from the lawn mower’s engine by loosening the screws with a screwdriver.
• Step 3. Locate the ignition coil: Remove the engine cover above the gas tank. You should now see an ignition coil.
• Step 4. Remove the lead: Remove the high-tension lead of the ignition coil from the spark plug and remove the spark plug from the lawnmower.
• Step 5. Remove the kill wire: Remove the kill wire attached to the ignition coil with the help of pliers
• Step 6. Take the coil out: The ignition coil can quickly be removed from the engine. Please remove it from the lawnmower to take it to the testing phase!

● Step 2. Test the ignition coil using a multimeter:

The ignition coil’s testing method is straightforward. All you need is a multimeter and the service manual for the engine used in the lawnmower.

• Step 1: Set the multimeter to 20K resistance measurement mode.
• Step 2: Now, look for the user’s manual of the service engine being used in your lawnmower. You can find one on the internet.
• Step 3: Look for the ignition coil’s resistance/tolerance value table inside the user’s manual.
• Step 4: Insert one end of the multimeter into the high-tension lead’s spark plug cap and place the other on the coil’s base.
• Step 5: The multimeter should give a resistance value within the range of the values in the table in the user’s manual.
• Step 6: Place one end of the multimeter on the coil’s kill wire terminal and the other on the coil’s base.
• Step 7: Again, the multimeter should give a resistance value within the range of the values in the table in the user’s manual.
• Step 8: Look for specific values in the table when the multimeter terminals are placed on the ignition coil’s particular points.
• Step 9: Similarly, place one end of the multimeter on the kill wire terminal, insert the other inside the spark plug cap, and note down the resistance value.
• Step 10: Suppose the multimeter gives values not in range of the matters mentioned in the user manual’s table or gives no values at all. In that case, your coil is faulty and needs a replacement.

● Step 3. Purchase a new ignition coil:

Now, as you have witnessed the test failure on the ignition coil, you finally decide that the option now is to buy a new one and throw the old one away! In doing so, you should ensure that the new coil being purchased should be the same as the one being replaced.

The critical thing to remember is whether one of your coils was faulty (if your lawnmower has two cylinders) or both.

If both of the coils are faulty, then both of these must be replaced with new ones. Consulting the lawnmower’s user manual and getting the engine number for your lawnmower is also a good option.

During the purchase, always ask the seller to provide you with the coil according to the particular engine model used in the lawn mower. At the moment, I checked the Briggs and Stratton ignition coil for my push mower repair.

● Step 4. Install the new ignition coil:

Are you tired after going through such a long process of testing and shopping? Don’t worry. You are almost at the point where your lawnmower gets up and running again. Just one more last step, and that is to install the new coil into the lawnmower.

– Install the spark plug:

Firstly, you need to put the spark plug back in its place. Connect the killer wire back to the ignition coil’s kill wire terminal. Next, click the spark plug cap off the coil to the spark plug. Place the coil’s screws back into their place, and tighten them just a little with the screwdriver’s help.

Here comes the most critical part of this installation process, so read it carefully!

The distance between the coil and the magnet on the flywheel must be kept at 10 points. So, for that, you can use a gauge and place it between the coil and the magnet, and then tighten the coil’s screws completely. Don’t have a meter? Don’t worry; we have a pro tip as well.

The business cards that we mostly have in our pockets all the time can also keep this distance. So, it can also be used to get the job done.

– Assemble the casings:

Moving further, install the engine covering and the plastic covering back and tighten their screws using a screwdriver. You are now ready to test the lawnmower as the testing installation process is now complete.

● Step 5. Test the lawnmower with the new ignition coil:

After all the day’s hustle, why not test the lawnmower and take it for a spin on your garden? Put the key back in and turn the ignition switch. Guess what? The lawnmower has started and is buzzing like it’s a new one! You can enjoy your day and make your garden even more beautiful. 

This time, let’s start with the kill switch and the plug cap of the magneto. I checked for any issues, and it seems to be working fine. Now, let’s kill the engine and see if it starts again.

RELATED QUESTIONS:

1. How can I verify whether the issue is with my lawnmower’s battery or coil? 

When your lawnmower doesn’t start, two possibilities may have caused this. Either your lawnmower’s battery is dead, or the ignition coil needs to be replaced.

A small test can be performed to check the issue with the ignition coil without opening the lawnmower’s engine and removing the coil to match it using the abovementioned method.

For this, first time, you must remove the spark plug cap from the hole. Then, drag the spark and hook it back up to the tension lead (the spark plug cap). Next, ground the spark plug against the lawnmower’s body and start the lawnmower.

If you see a spark produced from the spark plug, the coil is perfect and does not need a replacement. So, the problem might be with the battery or something else. But if no change in spark is produced, it implies that the ignition coil needs a replacement!

2. How can I test my lawnmower’s spark plug?

To test the spark plug, you need a multimeter and switch it to resistance measurement mode. Now place one terminal of the multimeter on one end of the spark plug and the other terminal on the other.

Suppose the resistance of the value displayed over the multimeter is above 10,000 ohms. In that case, your spark plug needs to be replaced, and if it’s below 10,000 ohms, it is perfect and does not need a replacement.

Remarks:

If you want to mow your lawn, but your lawnmower won’t start, the ignition coil may malfunction. But the lawnmower’s ignition coil can easily be removed, tested, replaced, and reinstalled at your home by reading this article.

Your safety is also our top priority, so don’t forget to take certain precautions while testing. Before starting the process, you must always wear work gloves to protect you from unnecessary cuts.

Besides, the wrench set and other tools must be used carefully and kept out of children’s reach. The magnet and the ignition coil also need to be cleaned after some time to remove any dirt or carbon to increase the coil’s life.

Finally, don’t forget to maintain the lawnmower’s other parts properly, such as filters, cutting blades, and oil. I noticed that regular maintenance can extend the life of your lawnmower by a year or more.