Bad Ignition Coil Symptoms Lawn Mower: 6 Fixes & Replacement Guide
The ignition coil, which also goes by the spark coil, is essential in starting a vehicle’s engine. It plays an important role in the ignition system overall.
If your riding lawn mower is difficult to start, if the engine only starts when you jiggle the plug wire, or if it performs poorly, it may be time to replace the ignition coil.
This article will teach you how to recognize the signs of a malfunctioning ignition coil in your lawnmower, as well as the most prevalent causes of failure and the solutions to those concerns.
Why Ignition Coil Is Important?
A lawnmower’s ignition coil is important since it is what transfers power from the battery to the spark plug, producing the spark that drives the engine into gear.
There won’t be any burning of oxygen and fuel in the combustion chamber for one or more cylinders if the ignition coil isn’t working. Because of this, they will refrain from firing. In such a case, the engine won’t get the juice it needs to move forward or even start.
6 Lawn Mower Bad Ignition Coil Symptoms
If your lawnmower’s ignition coil is bad, you may notice some of these symptoms. Don’t worry, I have added the fixes also.
Symptom-1: Mower Shuts Down Immediately
If the ignition coil is bad, it may cause the engine to shut down immediately or run very poorly. Depending on the severity of the problem, the engine may not even start.
If the ignition coil is bad, it will not effectively transmit the spark necessary to ignite the fuel mixture. This can cause a misfire, which will result in the engine shutting down.
The ignition coil on the lawn mower sometimes became overheated, resulting in an abrupt stop-down.
A qualified mechanic should inspect the ignition coil, spark plugs, and other components to diagnose and repair the problem. If the problem is found to be with the ignition coil, it should be replaced.
This, however, is the sign that a faulty ignition coil presents the vast majority of the time.
Symptom-2: Mower Not Turning Off
The most likely cause of a mower not turning off due to a bad ignition coil is a faulty ignition switch. This can cause the ignition coil to stay energized even when the switch is in the off position.
To fix this issue, the ignition switch should be replaced. If the switch is not the problem, then the ignition coil may need to be replaced as well.
It is also possible that the wiring to the ignition coil may be faulty, so this should be checked as well.
Symptom-3: Mower Begins Then Dies
If the engine starts and then dies immediately, it could be due to a bad ignition coil. The ignition coil is responsible for supplying the spark to the spark plugs. If it is not working properly, the engine will not be able to sustain itself.
The ignition coil should be checked and replaced if necessary.
Symptom-4: Engine Misfiring
Bad ignition coils can cause lawn mower engine misfires. The lawn mower’s ignition coil sparks the engine’s fuel. A misfire occurs when the coil fails to spark the fuel.
Check the spark plug wires for appropriate connection and condition to detect and fix misfiring. Check the spark plug next. Replace if worn, corroded, or damaged.
If the spark plug and wires are fine, the ignition coil is the issue. Use a multimeter to test continuity. Coils without continuity must be changed. Misfiring should stop after coil replacement.
Symptom-5: Poor Fuel Economy
The bad ignition coil of a lawn mower affects fuel economy because it will not be producing a sufficient spark to ignite the fuel. This means that the fuel is not burning efficiently, resulting in a decrease in fuel economy.
Additionally, the spark plug will not be able to ignite the fuel quickly enough, resulting in an increase in exhaust gases that can further reduce fuel economy.
To solve this issue, the ignition coil should be replaced with a new one.
Symptom-6: Engine Cranks
A faulty ignition coil may be the reason your lawn mower to crank but not start. The engine’s ignition coil sparks the combustion chamber’s fuel. Bad ignition coils can also prevent engine start-up.
Check the spark plug to find a bad ignition coil. Ignition coils usually cause no spark. Measure the ignition coil resistance with a multimeter. If the coil’s resistance is outside the range, replace it.
After replacing the ignition coil, check the spark plug gap and ignition timing to guarantee engine efficiency.
How To Detect A Bad Mower Ignition Coil?
Follow these simple instructions to determine whether or not the ignition coil on your lawn mower is functioning properly.
- Locate the ignition system’s rear lawn mower spark plug. Remove plastic coverings using a screwdriver.
- Remove the grounding wire and take the plastic boot off the spark plug.
- Clip one end of the spark plug tester to the exposed spark plug and place the long metal end into the plastic boot.
- Start the lawnmower. The ignition coil is functional if the tester sparks or the lawn mower starts.
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How To Replace The Ignition Coil?
The first step in fixing all those issues is a new ignition coil for your lawn mower. Here is the process:
Remove Ignition Coil
- Locate the ignition coil first. Remove the electrical plastic pigtail connector. Handle the connector carefully.
- Open the coil-to-engine screws. Remove the coil gently.
- Twisting the insulator boot slide removes the spark plug. Careful—it breaks easily. Remove trapped parts with needle-nose pliers.
- Remove each ignition coil in the engine. Remove them slowly.
- Check the spark plug inner section and boot for oil or anti-freeze after removing the coil and spark plug. Fix leaks and contamination.
Test Small Engine Ignition Coil
- Swap the suspicious coil with the other coil to start testing. The suspect coil will fail if the other cylinder misfires.
- A multimeter can also test the ignition coil’s primary and secondary windings. Replace the coil if the multimeter result is greater than normal.
Lubricate and Reinstall Coil
- Apply dielectric grease inside the ignition coil insulator boot first. It will waterproof the coil.
- Push the coil onto the spark plug gently.
- Install coil bolts. Reconnect the electrical pigtail.
- Finally, lubricate the coil connector with a little. Lock and fit the connectors and tab.
- Reinstall the remaining engine parts.
- Reconnect the negative battery cable.
- Check the lawnmower’s operation.
- After replacing the ignition coil, check it.
Precaution During Installation:
- Set the lawnmower’s parking brake.
- Flip the mower’s hood open.
- Get the engine cooled down to room temperature.
- When instructed, remove the negative battery cable.
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Frequently Asked Questions (FAQs)
What is the purpose of lawn mower ignition coils?
The ignition coil converts battery voltage into a spark that starts the mower’s engine. The flywheel and magnets run through the coil to spark your lawn mower. While the engine is running, the flywheel spins, magnets pass by the coil, and the spark plug fires at a specified time.
What is the replacement frequency of an ignition coil?
Ignition coils typically last 100,000 kilometers. Ignition coils fail near the mileage limit. to replace it. Other engine troubles can destroy the ignition coil. Replace the ignition coil if it has symptoms.
Why do Ignition coils keep failing?
Bad spark plugs can cause early ignition coil failure. Worn spark plugs ruin coils. Overvoltage causes heat. Heat melts coil wire insulation.