My Lawn Mower Starts But Then Stops. How Can I Fix It?

Ahhh…the scent of freshly cut grass. There’s nothing quite like it. But it can be not easy to get eager about taking on those massive green blades, only for the mower to go off and then stop working. When your mower gets started but then stops, you’ll want an immediate answer to what’s wrong and how to correct it. Here are the four most frequently cited causes for this problem with lawnmowers and what you should tackle each.

When your mower begins to run and then stops, it may appear as if you’re all alone. It’s much more common than you might think, and the solution isn’t that difficult.

Let’s examine the most frequent causes of an error and the best way to address them.

Reasons for lawn mowers starting and dying.

If your lawnmowers get started but then cease to run for a few seconds, then cease to function, here are the top four causes:

  • Carburetor dirty or clogged bowl
  • Old gasoline that is now bad
  • Poor or dirty spark plugs
  • There are too many gallons of oil in the reservoir

Below, I’ll go over the causes of each issue, how it may cause a mower to be running but then stops and then stops, and what you can do to correct it.

Dirty Carburetor or Clogged Carburetor Bowl

If your lawnmower starts but stops, the carburetor could be involved in some way.

Consider the idea. If you are in the northern part of the country, the mower is left to sit through the winter … in limbo for months, without doing anything.

This is especially true if you live in a cool climate and your lawnmower works hard all year.

In both instances, the carburetor will require some TLC.

How does a carburetor work?

Your engine requires a constant flow of gasoline to function properly. The carburetor is accountable for mixing gasoline with the appropriate amount of oxygen for combustion.

This engine provides constant rotation of the crankshaft, which is essential to operate an engine of the lawnmower.

If the carburetor in your car is dirty or the carburetor’s bowl is blocked, the procedure above may be compromised, and your engine could begin to run; however, it won’t function properly and could die soon after pulling the cord.

What can I do to fix it?

Your car’s dirty engine needs to be cleaned up with an aerosol bottle of cleaner for carburetors. This is just $10. It lasts for a whole season or two. I prefer WD-40 Specialist, Fast-Acting Carb/Throttle parts cleaner. This cleaner employs an alcohol-based formula to break down carbon-based pollutants, which leaves your carburetor clean and free of gum. It is a good idea to give your mower one shot every time I mow just before pulling the cord. I would recommend doing the same.

The only issue with the specific cleaner that I have reviewed is that it does not come with an appropriate straw to spray. Gumout makes a cleaner ( Amazon link) that can accomplish what you need with the jet spray application if you require an even more precise application.

You can purchase the product in person or on the internet.

Here’s the way to go.

Unscrew the carburetor and give it a thorough cleaning using the cleaner. Make sure you clean the hole and screw using the carburetor cleaner well. This is why the directional spraying straw comes in extremely useful. When you reattach the bowl, make sure you don’t tighten it too much. This can cause the threads to become damaged enough to deform the seal.

What Do I Do

To maintain your carbs, spray an icy spray to an air intake port of your mower’s engine before you begin to run it. It’s usually just next to an air filter. Take the filter off, spray an air spray to the area, and take it off and replace the filter.

If you begin the mower, it will be drawn into the engine and clear the carb.

Gas inside your mower is old

Make sure that you’re using quality gasoline in your mower.

If your mower’s gas has been inactive for a long time, the process of evaporated gas has likely left the dreadful substance.

The residue is a source of particles that cause a blockage to your mower’s internal parts.

The result is limited gas flow. This means the mower will start but cease to function within a short time. In some instances, the mower will not start at all.

What can I do to fix it?

If your mower’s tank isn’t more than 50% full of gas from the past, you could try adding new gasoline to lessen the impurities. If the gas you have is more than half the size of the tank, it will be best to take it out and then fill the tank with new gasoline.

Adding a fuel stabilizer, like a Stabil fuel system stabilizer, is recommended in both cases. Stabilizers stop the clogging of the residue for up to two years, and at just $10 per bottle, they’re an inexpensive and effective additive that can keep your mower operating as smoothly as a champ.

Always follow the instructions to find out the right fuel-to-stabilizer ratio for your lawnmower.

What Do I Do

I used to add Sta-bil to my fuel. However, now I only pay a small more for TruFuel 4 Cycle, an ethanol-free gas product that will last for a long time without deteriorating.

This is more costly than standard gasoline combined with Sta-bill. However, two cans of the larger size will see me through my Honda self-propelled lawn mower (this one is available from Home Depot if you’re curious) through the mowing time on the hill on the outskirts of New England. I enjoy the peace of mind which comes from knowing that my snowblower and mower always start on the first pull. I do not have to worry about a gas leak causing problems when I’m about to mow or clean the driveway.

It is available online or from Home Depot or some local hardware stores.

Filtering the spark is dirty or defective.

In order for your engine to run, spark plugs fire the mixture of fuel and air.

The small explosion will make your engine work.

Your mower’s ignition system relies heavily on spark plugs. If they’re dirty or defective, they’ll not start the mower, and it isn’t going to begin, or it could start and then die.

How can I fix it?

The spark plug(s) are simple to locate. Most walk-behind models are covered by a black cable located in the front of the Mower.

It is necessary to have a socket wrench that is the proper size to unbolt the plug (check the manual for the right size for the size of your mower/spark plug).

If the spark plugs you have aren’t excessively coated in the build-up, then you could attempt cleaning them. It is not recommended to remove a plug using the shot-blasting cleaning agent. A wire brush and the appropriate cleaner can do the job when the plug is dirty.

If your mower’s spark plug appears dirty or looks like it has an odor of carbon, it is best to replace it.

This is a straightforward, inexpensive job: A new spark plug will cost between $8-9, and the size you require is likely to be in stock locally.

What do I Do

Spark plugs must be replaced each year or so to ensure that mowing is smooth and easy. I do my own every year in the spring as an element of spring mower maintenance.

I purchased new air filters and also changed the mower’s oil all at once. It costs me around $20, takes approximately 15 minutes, and keeps my mower in good working order.

Replacing Your Spark Plug

Removal of the spark plug is a straightforward task that anyone can complete. Disconnect the spark plug wire and remove the old spark plug with a spark plug socket.

The process of replacing a spark plug may be a little more difficult for the first-timer. However, I would still consider it to be an easy task.

Use a gauge for your spark plug to determine the gap between two electrodes on the top of the spark plug. Examine the specifications for your specific model to find out the recommended dimensions that the gap should be.

If needed, you can employ an instrument to alter the distance by gently stretching the electrode. If the gap is in good shape, it will move slightly as you push it into the gap.

Then, you can put in the new plug and connect the spark plug’s wire. Be cautious not to tighten too much during installation.

If you’ve never attempted the same thing before, then several videos on the internet are extremely helpful. Still, I suggest starting when it feels comfortable, taking it off for no more than a quarter-turn to ensure no injury.

There is too much oil within the Mower’s Reservoir.

If your carburetor is in good condition and the spark plugs are functioning, it could be because of excessive oil.

It’s human nature to fill up a lawn mower’s oil reservoir, particularly if you’re not the handiest. Having accomplished the task yourself, it’s a feeling of accomplishment that you decide to go overboard and fill the tank to the max.

It happens, and it’s all that bad (or your lawnmower).

Smoke coming out of your engine could be a clear indication that oil levels are too high—the reason.

If you notice a lot of smoke is visible on the mower, it may be on; however, not for a long time. In this scenario, the excessive oil will eventually cause the engine to drown and cause it to stop working.

How can I fix it?

It’s a simple solution. If you’re accumulating excess oil, all you need to do is remove some. You can do this by using the siphon, or (if you have a walk behind mower) you can tilt your mower and then take the oil out of the hole in which you put it.

What do I Do

I’m guilty of overfilling my tank with oil at times too, and I’ve learned not to rush when adding oil. I always do it again using the dipstick and slowly bring the level to the right level.

If you’ve overfilled the tank with oil, I suggest using dipsticks to determine the amount of oil that remains in the reservoir before taking it out to ensure you’ve got the correct amount.

Insufficient oil is a different (and more significant) issue, and you do not want to trade one issue in exchange for another accidentally.

After draining the oil and determining whether you have the right amount, turn the mower over.

If the mower is lit and runs without blowing smoke puffs black smoke, then you’ve solved the issue.

Lawn Mower, It’s a good idea to start it and then stop. It’s time to call a professional

If you’ve tried each of the strategies I’ve provided to fix your lawnmower that is running and stops working, your issue has been solved.

If there is no sign of it, then it’s time to put away the towel and call an expert.

Other problems could hinder your mower from working correctly.

More serious reasons why your lawn mower is Starting, But Then Stops

  1. A worn-out carburetor If your carburetor is more than just dirty, then it’s time to change it.
  2. A faulty choke: Unless you are exceptionally skilled, recognizing the issue and fixing the delicate balance required to make your engine purr as a cat is an issue that is best left to the professionals.
  3. Gas tank blockage or gas line When your gas isn’t reaching the engine, the mower will not be running properly. Blockages of any kind that hinder gas flow may require a trained eye to spot and repair.

A typical weekend worker with no knowledge of the subject will likely be more comfortable hiring someone who has the knowledge and the equipment to do the job properly.

I would suggest you begin by examining the warranty of your mower. If it’s covered, then repairing it could not cost anything. Certain businesses will send a technician directly to your house or collect your mower to speed up the process.

If your mower doesn’t have a warranty, locate an area small-engine repair shop with a good reputation. They can repair almost everything, and their costs tend to be lower than what you’d think.

Maintaining your lawnmower is the best way to avoid problems

The best way to make sure your mower is ready to go and perform like a pro is to set the necessary preventative measures in place.

I’ve suggestions to winterize your mower and the spring-time maintenance guide, which you can go through if you’d like to know more.

To summarise them here, however, to summarize them:

  1. Clean your air filter often (replace it every year).
  2. Change your spark plugs once every two years.
  3. Make sure that the gasoline and oil you store are in good condition. Utilize a stabilizer in your gasoline to ensure it stays fresh for two years, or you can pay an extra fee for a four-cycle TruFuel.
  4. By using an engine cleaner, you can make sure your engine is clean.
  5. Use the dipstick to ensure you make sure you don’t fill your reservoir too full.
  6. Make sure your carburetor is clean by using the use of a cleaner spray for your car.

Conducting regular maintenance on your Mower is ideal to ensure that it is running well, and spending just a few dollars per year on this will be worthwhile.

You’ll be able to avoid headaches and repairs, and you’ll have your lawnmower for a long time. It will start immediately when you require it.

If you have an issue with your lawnmowers, determine whether you’re comfortable fixing it by yourself.

If the issue appears to be a bit more than the basic, do not hesitate to contact an expert. There’s no excuse for this, as sometimes DIY repairs aren’t worth the time, effort or frustration.

If you’re ready for the challenge of fixing the problem on your own, The above suggestions are the best starting point as well as online videos could be helpful. I’m convinced that YouTube is an incredible source.

The most important thing is you fix your Mower to allow you to take it out to create a lawn that is the envy of all the neighbors.

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