Why Is My Lawn Mower Not Firing? (How To Troubleshoot)

Have you ever undergone a situation where your lawn mower won’t fire up? If yes, you must have wondered what might have gone wrong and whether it is possible to troubleshoot this issue. You must have also wondered how to troubleshoot such a problem, right?

Firstly, test whether there’s any Spark or not. Next, remove all cover parts to access the Ignition coil. Then, remove the older one and install the new Ignition coil accordingly. Adjust the Gap between the Flywheel & Ignition coil. Lastly, reinstall all the parts & recheck the Spark.

Thus, continue reading the following article and learn how to troubleshootwhy is my lawn mower not firing.

What Causes the Problem?

A lawn mower might experience no firing or no spark issue due to defective internal elements of the ignition system. Such as faulty Armature or ignition coil, broken or damaged spark plug, or loose or disconnected internal wiring connections.

Not firing trouble can also arise on a lawn mower due to a bad plug gap, a wrong gap between the flywheel and the ignition coil, loose or disconnected coil control wiring, faulty grounds or shorts, and a defective stop/start switch.

However, all of those are just assumptions based on most users’ and experts’ experiences. You can only confirm the actual culprit of such commotion after you have thoroughly investigated all the possible faulty areas.

5 Steps to troubleshoot why is my lawn mower not firing: 

Lawn mower users often complain about why is my lawn mower not firing.

It can arise due to various reasons such as dirty or worn-out spark plugs, bad ignition coil, kill switch malfunctioning, defective stop switch, broken wires, shorts, or ground issues.

But you cannot verify until you have investigated all the possible foul areas to confirm the main defective part.

Inspecting each and every possible internal area is a great way, but it can be time-consuming and expensive too.

In that case, most people prefer a short and simple way to fix the problem.

That’s why I have enlisted a quick, simple, and cost-effective DIY method to troubleshoot such issues.

Things needed to troubleshoot why is my lawn mower not firing:

Have a proper glance at the checklist of the required tools and materials:

ToolsMaterials
Standard Mechanical tool boxNew ignition coil
Safety Gloves & Goggles

Step 1- Test whether there’s any Spark or not:

First, start the process by removing this spark plug.

Test whether there’s any Spark or not

Next, put the plug back in here, and reconnect it.

Test whether there’s any Spark or not 2

Then, lean it here against the engine block and try to start your lawn mower engine to check if there’s any spark.

Test whether there’s any Spark or not 3

You can see in the below image there’s no spark, right?

Therefore, you need to check on the ignition coil next.

Step 2- Remove cover parts & access the Ignition coil:

First, remove all the cover parts that shield the ignition coil here.

Remove cover parts & access the Ignition coil

Keep removing all the parts until you reach the flywheel and ignition coil.

Remove cover parts & access the Ignition coil 2

Now access to the ignition coil here.

Remove cover parts & access the Ignition coil 3

This little black wire, that’s your kill switch wire.

In case, it is loose and leaning against something else, then that’s already a problem. So, make sure that the wire is correctly assembled. Otherwise, there will be no spark or no firing.

Remove cover parts & access the Ignition coil 4

Then, you have this gap between the flywheel and the ignition coil. Thus, make sure that gap is correct.

Remove cover parts & access the Ignition coil 5

Next, remove the nuts.

Remove cover parts & access the Ignition coil 6

Then, carefully remove the ignition coil by disconnecting the wire as shown in the picture.

Step 3- Install new Ignition coil:

Install new Ignition coil

If the ignition coil looks bad in shape or condition, replace it with a new one.

Install new Ignition coil 2

Now connect that wire to the new ignition coil and reassemble the ignition coil in the same way as you removed the older one.

Install new Ignition coil 3

Step 4- Adjust the Gap between the Flywheel & Ignition coil:

Next, you need to adjust the gap between the flywheel and ignition coil.

Adjust the Gap between the Flywheel & Ignition coil

Take a simple piece of paper and fold this in half.

Now see these magnets here, and those magnets should be right in front of the ignition coil.

Adjust the Gap between the Flywheel & Ignition coil 3

So, loosen the brake to move the magnets in front of the ignition coil.

Since it’s magnets the ignition coil is going to draw.

Adjust the Gap between the Flywheel & Ignition coil 4

So, pull the ignition coil away a little bit and take that paper to put in between.

Adjust the Gap between the Flywheel & Ignition coil 5

Now, it’s easier to tighten the screws securely. When you have successfully secured the screws, remove the paper.

Adjust the Gap between the Flywheel & Ignition coil 6

Tips: Remember gap distance between the flywheel and the ignition coil should be point 1 and point 3 millimeters.

Again, loosen the brake and rotate the flywheel to ensure there are plenty of gaps and no contact between them.

Step 5- Reinstall all the parts & recheck the Spark:

Now, put back all the upper parts that you previously removed to access the ignition coil.

You can even take pictures of every step; in case you mess up later on.

Then, connect the spark plug against the engine block and pull the bolstering. If you can see the spark, it means your problem is solved.

Next, put everything back together and fire it up to see what happens. If it is working, you are good to go now.

Reinstall all the parts & recheck the Spark

If you still see that your mower not firing up, contact the nearest dealership for professional assistance.

Warning:

Performing such troubleshooting tasks can be hazardous. Thus, make sure you have enough knowledge and expertise to perform them. Always read your mower’s instructions manual first before operating, servicing, or troubleshooting it.

Watch this video.

Frequently Asked Questions (FAQs)

What causes a lawn mower not to get any spark?

It can occur due to defective wires, faulty spark plug lead, shorts, grounds, damaged ignition coil, or a damaged stop switch. 

What happens if the spark plug does not ignite on a lawn mower?

If the spark plugs on your mower fail to ignite or fire up, it can cause an engine misfiring or complete starting failure issue.

Why does my lawn mower cylinder not fire up?

When you notice that your lawn mower engine has started to misfire, it’s obvious that one or more cylinders are not producing enough power. Such failure can arise due to a fouled spark plug, faulty oxygen sensor, or clogged fuel injector.

How to determine when your lawn mower ignition switch is bad?

Common symptoms such as a stuck ignition key, the engine doesn’t turn on, unable to move the ignition key back and forth or engine cranks then die will alarm you about a bad ignition switch.

Can a bad ignition coil on a lawn mower cause no start trouble?

Yes, it can. When the ignition coil turns bad, it fails to transfer the required voltage, and the engine will fail to fire up. This will eventually lead to a no-start situation.

Final Verdict

Initially, the whole procedure might seem a bit complicated to perform, but with minimum mechanical expertise, you can easily fix the issue by thoroughly following the steps explained above.   Thus, if you encounter similar issues with your lawn mower in the future, do not wonder why is my lawn mower not firing. Instead, try today’s DIY technique to fix it.

Related Posts:

Similar Posts