B&S push mower starts and stalls after refueling. Push mower starts then dies

BS push mower starts and stalls after refueling

I’ve very recently had some trouble with a push mower I bought last fall. A couple weeks ago, the engine died a couple minutes after I started mowing. Turns out it was out of gas, so I refilled it. However, once it was re-filled, the engine would die within a second of starting again. I put oil in the tank, added some stabilizer (which also has some fuel-line-cleaning additives), and no luck. I read that this sounded like a carburetor problem, so I took off the bowl and dumped the fuel that I found sitting in there. I had expected to see the jets clogged, but I instead found them completely clear. Disappointed, I put everything back together and gave it another start. This time it ran, and I hoped that this meant that I had just flooded the engine. Fast forward a couple weeks. The engine runs out of gas while I’m mowing; this time the tank is bone dry. I refuel, add more fuel stabilizer, and it starts just fine, but after a moment, it dies again. After a few tries, it’s back to stalling immediately after it starts. I took the carburetor bowl off again, dumped it, and replaced it, but this time it didn’t work. Suggestions? Further Information This is Hyper Tough mower with a Briggs Stratton 300E engine, the kind with an all-plastic carburetor.

I have noticed with my BS mower that if i fill the fuel tank too high, some fuel will pass into the housing for the air filter, and it won’t run. I’m careful now to not fill the tank to the top and the problem has gone away. However, I’m not sure that my explanation is accurate (I’m lazy—once a problem is gone I lose interest in determining the cause).

I happened to have a new air filter so I put it in and it started right up. i was also careful to keep the mower level ( I have some hilly areas) until the level of gas inthe tank was down some.

Understanding Your Carburetor

In order to fix your lawnmower, you will first need to understand how your carburetor works. Concerning other motors, if you own a motorcycle or any other small gas-powered engine, then you have a carburetor. The primary function of the carburetor is to mix the gas and air. It does this to make it more combustible and allow the pistons to burn.

Carburetors mix precisely the right amount of oxygen and gas. This is called AFR (Air Fuel Ratio). After starting your engine, gas will flow from the tank and will go into the carburetor bowl. Inside the bowl, there is a floater, and this controls gas going in and out of the bowl.

The Function Of Your Carburetor

As you start the engine, the air is sucked through the vent. Then, air pressure atomizes the gas and mixes this with the oxygen. This mixture will spray into an even more refined form and go into the spark plug chamber. It now creates a spark, and the engine will run.

Essentially, if your lawnmower starts then dies, you should first look into the carburetor. You can also look into the items that are also attached to it. Here we identify the common problems the carburetor has and also the best solution to fix these.

Reasons Your Lawn Mower Starts, Then Dies

If You Have A Loose Carburetor

If you have a loose carburetor, then your engine will not function properly. This is because you will not have a full flow of gas, nor will the atomization of gas be stable. To avoid this, check to make sure the carburetor is firmly attached. This can help you to know if you have serious problems or if you simply need to tighten your carburetor.

On the other hand, your problem could simply be that your carburetor is attached too tight or the wrong way. If this is the issue, then you will need to adjust it accordingly to get it to allow your mower to start.

Is Your Carburetor Clean?

This is incredibly important if you want to see if your carburetor is working. Make sure to clean it with a carburetor cleaner and get off all the dirt and grime that has built up. This is a straightforward fix and might allow your mower to start.

It’s a good idea to take the time to clean your carburetor regularly. You should look at it at least once every couple of months and then clean it as needed. This will help you stay on top of any problems that may eventually arise in the future.

Clogged Carburetor Bowl

Since most carburetors today have their carburetor bowl underneath, attached by a screw with a hole at the bottom, it is very easy for this hole to get clogged. When this happens, air won’t be able to pass into the carburetor. This prevents the downward movement of gas and will cause your lawnmower to stall.

To fix this, remove the bowl screw. You can do this by using a ½ inch plug wrench. Be sure to clean the dirt out of the bowl and then out of the screw as well. If you cannot wash it easily, take a very small wire and thread it to remove any dirt.

Once again, take your carburetor cleaner and spray the hole. As you go to recap the bowl, try not to overtighten the screw as this can affect the seal.

Residues From Old Gas

When you leave gas out for a long period of time, often it can form a residue. These residues can clog the parts of your carburetor internally and then restrict the gas inside. To remove these residues, you should drain out the old gas and replace it with fresh fuel.

Be sure to add a fuel stabilizer as well, as this will enhance your fuel quality and prevent future residues from forming. Using a fuel stabilizer can make your gas usable for up to two years.

Dirty Or Defective Spark Plug

If you have a dirty or non-working spark plug, it might be due to a huge amount of carbon build-up. This typically happens in the socket of the spark plug and will eventually weaken it.

Always make sure your spark plug is not worn out. Check the spark cap for dirt as well. If you do see signs of carbon deposits or oil, be sure to clean it up. Unfortunately, sometimes the only answer is to replace it.

Blocked Gasoline Cap

Although not all do, some gasoline caps have holes in them. This can help to stabilize air pressure inside your gas tank. If you do happen to have these holes on your machine, if the holes get blocked, you will have a major issue.

Basically, the blocked hole creates a vacuum in your tank. This will once again disrupt the gas flowing into the carburetor. The fix for this is simple, clean the hole with a small wire. If the cap is damaged, you should purchase a new one.

Too Much Oil

Although you would never assume this would be a problem, if you have too much oil in your machine, then you may have too much fat in your oil reservoir. Always be sure to clean your carburetor first.

If you have cleaned your carburetor, your engine stalls, and there is also white smoke coming out of the engine, then that is a sign of too much oil.

Old Carburetor

If you have been using your Briggs and Stratton lawnmower for many years, then your carburetor might eventually fail you. Whether you simply need to repair it or you need to replace it, these are great lawnmowers and are worth fixing.

If your carburetor is old, bring it into a home improvement store where they sell mower parts. Tell them that you want to order that same type of carburetor so that you ensure you replace it with the correct model. Otherwise, you will find that your mower doesn’t start again.

How Much Does A Carburetor Cost?

At Home Depot, the price for a Briggs and Stratton carburetor costs around 25 before tax. Also, they sell a carburetor cleaner for 6500 to 4 per can. So, by providing the correct maintenance, you can forgo the 25 and pay just 6500 to 4 a month to keep your carburetor clean.

Although, even if you had to replace the carburetor, it still doesn’t cost that much! That’s relatively cheap for a necessary part. However, if you were to bring it into a shop for a specialist to repair it, then it will cost you between 100 to 180 depending on the amount of time and the shop that you take it to.

Related Questions

How do I know if I have too much oil in my reservoir?

Tilt your lawnmower up and put a heavy object on the handle. This should hold it up. Allow the oil to go to other parts of the engine; leave it for about an hour. Then run the machine and see if it runs for a while without dying. If this happens, then you simply have too much oil.

How long should I go without cleaning my carburetor?

Cleaning your carburetor every six months is a good idea. If you are a commercial business and use it more often, then you may want to do so even more often. Maintenance is key to keeping healthy machines.

How often should I change my oil?

You should change your oil either every 25 hours of use or every season.

How To Fix a Lawnmower Which Runs Then Dies

Starting up your lawnmower only to hear the engine die shortly after can be worrying, and leave you wondering what the issue is with your mower and the solution to fixing it.

push, mower, starts, stalls

If your lawnmower is starting up then going dead, this is likely due to either the fuel, carburettor, a bad spark plug or too much oil in your mower. Any of these issues can be reasons for your mower to struggle starting but luckily can be easily remedied too.

So to make things easier for you, we have put together a troubleshooting guide with solutions so as you can determine what the issue is with your mower and how to solve it.

Common Reasons As To Why Your Lawnmower Is Starting Then Dies

One of the most common reasons as to why a lawnmower is starting then dying can be due to a blocked or dirty carburettor, however, there are also a couple of other possible reasons that should be explored too if your carburettor is not to blame.

Have we listed them out along with the solutions below.

The Carburettor Has Issues

Before we get on to the other start-up issues that can occur with your mower, let’s tackle the most common one first.

A carburettor on your mower is one of the most important components as it is responsible for mixing air and gas within your mower, allowing it to run properly. A clogged or dirty carburettor can stop this process from taking place, causing your mower to die, this often happens when the mowers has not been used and left to sit in storage for a while.

Symptoms of a blocked carb could be your mower starting then dying, black smoke, or using too much fuel, the blockage happens from old fuel.

Your carburettor may also be too loose.


To fix a loose carburettor, you simply need to tighten it. If you suspect that your carb bowl is blocked, then you will need to clean it with a carburettor cleaner to fix the issue, always ensure not to overtighten the bowl when you put it back in place.

The Fuel Has Gone Bad

Next up on our list is the fuel in your mower. Fuel can start to go bad in your mower quickly, and when left for a long time will start to partially evaporate which can cause residue to build-up and block the lawnmower from getting enough fuel during use, causing it to die unexpectedly or even not start at all in some cases.

push, mower, starts, stalls


The good news is, in most cases, this issue is pretty easy to fix and will require you to drain this old fuel out and put new petrol in. We also recommend adding a fuel stabiliser to prevent residue from building up in the future when left in your mower.

There’s Too Much Oil

We can all get a little carried away with our mower maintenance sometimes and end up over-filling the oil reservoir of our mower. Some symptoms of this problem are white smoke or start-up issues.

push, mower, starts, stalls


To fix this issue, drain the excess oil and see if it solves your problem, to stop it from happening again you should pour your oil slowly and use a dipstick to measure it out.

You Have a Damaged Spark Plug

A spark plug is essential to starting-up your mower as it makes the spark between the fuel and gas to power the lawnmower on, when this plug becomes damaged or dirty, it can give start-up problems with your lawnmower.

Check the spark plug for any signs of damage or carbon build-up.


Remove the spark plug from your mower and give it a good clean, if it is still not working when you reattach it to your lawnmower then you might have a damaged plug.

In this case, just replace the whole spark plug, doing so should not cost you a lot and save you the hassle of trying to fix it. Spark plugs should be replaced every year anyway.

push, mower, starts, stalls

A Blocked Fuel Cap

One of the less common issues that can stop your mower from running properly is a blocked fuel cap.

You will find a hole within this cap that let’s airflow to the fuel tank and move the fuel from the tank to the carburettor.

When this gets stuck, you may find that the fuel in your mower can not reach the engine of the lawnmower, causing it to die or not start.


Remove the fuel cap and clean the air hole with a small wire brush so as the air can pass through freely again. Also never overfill your mower with fuel as this can make the fuel enter through this airhole when it expands from the heat.

push, mower, starts, stalls

The Choke Is Not Working

Flooding can be a common issue caused by a choke, whether it is left on for a few seconds or stuck in the on position, this choke can mean that fuel will flood the combustion chamber of your lawnmower and stop it from producing a spark.


To try and fix the choke problem with your mower, you will have to open it up and let the engine restart itself, you can try pulling your mower to start on a half choke and let some air enter the chamber of your lawnmower.

If none of this is working and you suspect the choke is the cause to blame, take it to a professional who can fix the issue.

How To Maintain Your Lawnmower Avoid These Issues

push, mower, starts, stalls

We hate to say it, but, most of the issues above tend to be caused by someone not doing regular maintenance on their mower. Tasks such as draining the fuel tank for storage and changing the spark plug are part of caring for your mower and can stop larger problems from occurring.

To help you out, we have listed out some essential maintenance tips to keep your petrol mower in the best shape possible below.

Frequently Asked Questions About Why My Lawnmower Is Starting Then Dies

What is the carburettor on my mower?

The carburettor is a component in your mower which mixes the fuel and oxygen and allows it to flow up into your mower’s engine.

How quickly does fuel go bad in your lawnmower?

Fuel will start to go ‘off’ in your lawnmower in as little as just 30 days, meaning you should never store your mower away without draining the tank first or adding some stabiliser.

If my mower is blowing white smoke from excess oil, should I worry?

No, this is the natural response of your mower to the increased amount of oil, you can let the smoke burn out after you have drained some of the excess oil. If the white smoke continues after doing this then you might need to start troubleshooting other reasons.

push, mower, starts, stalls

Final Words

Overall, start-up issues from your mower can be concerning, but are luckily nothing to worry about as long as you can determine what the problem is and fix it with our guide above. If you are ever unsure about fixing certain parts of your mower it’s best to take it to a professional, as trying to fix it yourself can do more harm than good!

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Lawn mower starts then dies? This is how you fix it

push, mower, starts, stalls

There are very few things in the world more annoying than when your lawn mower starts then dies. You have to stop what you’re doing and try to figure out the problem just to get a little bit of yard work done. The good news is that there are plenty of ways to troubleshoot lawn mowers and be up and running in no time.

Common problems with lawn mower brands

The first thing you have to consider when your lawn mower won’t stay running are the common problems that you run into with most lawn mower brands. Most people have issues with their lawn mower after they haven’t used it for a while, like the first time they break it out after a long winter. As a result, your lawn mower can develop some problems during idle times and need a little coaxing to start properly again.

Some of the most common issues you’ll encounter relate to the fuel and the carburetor. If your carburetor is full of gunk, you’ll want to get a socket set and some carburetor cleaner to get rid of all of the buildups. You can get both of these items at virtually any hardware store. Carburetor issues are one of the primary reasons why your lawn mower starts then stops because they prohibit the lawn mower from getting the fuel it needs to stay on.

You’ll also want to look at the air filter and spark plug. Sometimes your spark plug can get damp during the winter, rendering it ineffective. Remove it, clean it, and allow it to dry thoroughly. You’ll also want to change the fuel for good measure. Sometimes old fuel can cause internal issues in your lawn mower and even damage it further.

Make sure that you put fresh fuel in your lawn mower, and you should be in business in no time.

push, mower, starts, stalls

Craftsman lawn mower starts then dies

Craftsman is one of the top lawn mower brands on the planet, but even these great models can have some issues when it comes to running correctly. For example, if your lawn mower starts then stops after a few minutes, you likely have a clogged carburetor. Carburetors regulate air and fuel flow within the lawn mower, so it’s imperative that they’re clean and obstruction-free.

Carburetors generally get clogged up when you leave old fuel in the mower for an extended period of time. So if you try to fire up your Craftsman after the winter and find that your lawn mower won’t stay on, it’s probably because old fuel got into the carburetor during the long winter and caused it to malfunction.

Fortunately, it’s easy to clean your carburetor. Simply invest in some carburetor cleaner from your local hardware store, and remember to change your gas more frequently. Most of the time, gas is only suitable for a month or so. So if you don’t use all of your gas before 30 days, or if you’re putting your Craftsman lawn mower away for the winter, flush out your gas.

push, mower, starts, stalls

Toro lawn mower won’t stay running

There could be plenty of reasons why your Toro lawn mower won’t stay running. The most likely culprit is a problem with the combustion process, specifically an obstruction that prevents gas or air from circulating within the machine. There could also be an issue with your Toro’s spark plug.

Toros tend to be particularly susceptible to moisture in their engines. If your engine is wet, you’ll find that your lawn mower sputters and dies. Fortunately, there is a relatively easy fix for this common problem. Remove all of the gas from your tank, flush it out, and put in fresh gas.

If changing the gas doesn’t work, try looking at the fuel filter. Sometimes if you leave your lawn mower dormant for too long with old gas in it, debris can clog up the carburetor and fuel filter. Simply swap out your fuel filter, give the carburetor a good cleaning, and you should be back in business.

If your lawn mower shuts off suddenly, you might have a problem with your spark plug. Occasionally, you can dry and repair wet spark plugs, but sometimes you need to replace them. You can get a new spark plug for your Toro lawn mower from any authorized Toro dealer or online.

push, mower, starts, stalls

Husqvarna lawn mower won’t stay on

If your Husqvarna lawn mower starts then dies, you might be looking at either an electrical or mechanical shortcoming. If you’re firing up your Husqvarna right after the end of winter, you might find that your riding lawn mower runs for a while then dies, which can cause significant problems if you’re trying to mow a larger piece of land.

The first thing that you need to do is ensure that your parking brake is properly off. Husqvarnas will not start properly if the parking brake is on. If the brake is fully off, it’s time to drill down into what the issue could be. One of the primary reasons why your riding lawn mower starts then dies is damage to the drive belt. Replacing the belt will undoubtedly solve the problem. You can get good replacement parts at any authorized Husqvarna dealer.

You might also be looking at an electrical issue. Husqvarna riding lawn mowers use Operator Presence System to avoid accidents and malfunctions. Although the vast majority of the time, this works in your favor and keeps you safe, it can experience some dysfunction if your electric sensors are off. Husqvarnas are designed to stop when you leave the driver’s seat. If the wiring is bad, the machine might stop suddenly, even when you’re in the seat.

Unfortunately, unlike many of the common problems on our list, electrical issues aren’t as easy to fix. If you suspect that this is the problem, take it to your authorized Husqvarna dealer. Keep your Husqvarna riding mower happy and running like a dream by keeping the carburetor clean and replacing the gas every thirty days. Make sure that you drain the gas fully before putting your lawn mower away for the winter.

These tips can also apply to other riding lawn mowers. If your John Deere riding mower keeps stalling, follow the same advice that you would use for Husqvarna, and take it into the dealership if you suspect an electrical issue.

push, mower, starts, stalls

Other possible reasons why your lawn mower won’t stay running

There are a few major reasons why your lawn mower won’t stay running properly. You might have an issue with old or gunky fuel, your carburetor could be blocked or dirty, or the ignition could be compromised somehow. Cleaning your carburetor, changing your gasoline, and swapping out your air filters will probably do the trick. Additionally, you might need to clean or replace your spark plugs.

In the case of riding mowers, your power brake might be activated, or you could have an electrical issue. While most of these problems are ones that you can solve at home, never attempt anything too complex that you feel is beyond your ability. Lawn mowers are expensive pieces of equipment, and if you’re not sure what you’re doing, you might exacerbate the problem.

push, mower, starts, stalls

Lawn mower starts then dies

It can be exceptionally frustrating to have a malfunctioning lawn mower. You might be asking yourself, “why does my lawn mower only run for a few seconds then die?” A very common cause is fuel contamination. When you leave fuel for too long in your lawn mower, it can evaporate and get sticky. This gunky, leftover fuel gets into your fuel line and carburetor, rendering them ineffective and unable to move air and fuel around the inside of your mower.

Additionally, if your lawn mower’s interior gets wet, it could develop internal condensation, damaging the spark plug or the air filters. Condensation is one of the leading reasons why your lawn mower doesn’t work properly, especially after a long winter.

Make sure that you totally drain your fuel and clean your lawn mower before putting it away for the winter. Additionally, it’s a good idea to keep your lawn mower in a dry, relatively warm spot to discourage internal condensation and keep it safe until spring.

You should also make a point to change the air filter regularly. Air filters are inexpensive, you can get them anywhere, and they’re relatively easy to swap out. Simply changing the air filter will keep your lawn mower running more effectively and stave off bigger problems down the road.

For the most part, you should be able to fix your lawn mower at home. Usually, problems come down to just a few root causes, and you can take preventative measures to ensure that your lawn mower is safely stored moving forward. To avoid major headaches, check your lawn mower before taking it out, especially after a long winter.

Check the air filter, spark plug, and fill it with fresh, clean gas. This will give you some peace of mind and ensure that your lawn mower runs smoothly without stalling.

Is your lawn mower not starting after standing still in the winter? Try to fill it up with fresh fuel.If this isn’t working check out ‘common problems with lawn mower brands’.

Changing your gas may help sometimes but not always. if you want to find out another solution, take a look at ‘Toro lawn won’t stay running’.

There are multiple problems that can occur on your lawn mower. although there are a lot of problems that you can fix on your own.Check out this blog for all the solutions and after nothing has worked you can call your supplier.

How Do You Fix Lawn Mower That Starts Then Dies?

Loose Dirty Carburetor

A loose carb won’t let your engine function as it will create insufficient flow and atomization of gas. Check your carburetor is secure before proceeding.

To ensure all parts work on your carburetor, cleaning the carburetor with a carburetor cleaner is the first step since the build-up of gunk is a reason for your mower to start and stop.

push, mower, starts, stalls

Dirty or Defective Spark Plug

Even if you have a new spark plug, check it anyway, as carbon build-up can weaken the spark or stop it from sparking altogether.

You’ll need to clean it up and wipe the covered electrode of carbon deposits and oil. It is worth changing these as part of your regular maintenance. Also, check the plug wire as these can crack and break over time.

Clogged Carburetor Bowl

Most carbs have a carburetor bowl beneath them. You’ll find a screw in the bottom of the bowl and a hole that supports the bowl. If the hole in this screw is clogged, air can’t pass from under the carburetor and won’t regulate the movement of gas.

Remove your bowl screw using a 1/2-inch plug wrench, then clean the dirt out of the bowl. At the same time, clean the dirt in the hole using a thin wire. Spray in the hole with carburetor cleaner. Your fuel system is the key to an effective running mower.

Blocked Gas Caps

Some gas caps have holes in them to help stabilize air pressure.

When this gas cap vent is blocked, it creates a vacuum in the tank where there can be a disruption of gas flowing toward your carburetor. Clean any hole in the cap with a thin wire or replace it with a new one if the cap is already beaten up. (Find the Best Mulching Lawn Mower)

Too Much Oil

One thing that can crop up is when you have done the above; you have an overfilled oil reservoir. You can spot this if your mower smokes. You can drain this or let it burn off through use.

push, mower, starts, stalls

Q: I can’t seem to figure out why my lawn mower won’t stay running. There’s plenty of gas and oil in it. Can it be repaired, or is it a lost cause?

A: Lawn mowers seem like simple machines, yet they require some TLC to operate smoothly—especially if they’ve been sitting in the shed for a while. A full gas tank and oil reservoir are the essential first steps when checking why the lawn mower won’t stay running, but the problem could also be a dirty filter, clogged carburetor, improper fuel mixture, or a dirty spark plug. If you’re ready to get your hands dirty, check out these troubleshooting tips to get your lawn mower running again. However, you may need a lawn mower specialist to get you back to trimming your grass. Alternatively, a landscaping professional can take care of it for you.

The fuel might be old and dirty and needs to be replaced.

Fuel that has sat in the motor for a while can evaporate and leave a sticky residue. The inlet and outlet ports leading to the carburetor could be clogged, as well as the fuel filter. In cold, wet winter seasons, condensation can collect inside the tank, which doesn’t mix with the fuel. Replace old, dirty, or diluted fuel; adding fresh fuel to it won’t solve the problem. Drain the old fuel out of the tank and collect it to be disposed of safely per local requirements. Clean off the carburetor ports before refilling the tank.

The air filter might be dirty, which prevents it from getting enough air.

Motors have air filters to collect and trap dust and debris that could clog the machine’s inner workings. Over time, they become clogged and need to be replaced. If an air filter isn’t working correctly, the motor can’t get enough air to prevent overheating. Inspect the air filter for carbon deposits or oil, and replace it if it’s contaminated. Paper filters always need immediate replacement if they’re contaminated, but a dusty foam filter could benefit from being washed and dried at least once before replacement. It’s recommended to replace the air filter after every 25 hours of use.

The carburetor might be clogged and dirty.

One inconvenient reason a lawn mower won’t stay running is a problem with the carburetor, which mixes the air and fuel for internal combustion. The carburetor bowl may be clogged, or the inlet and outlet ports are slimy from fuel residue. Remove them and spray them with an aerosolized carburetor cleaner (not water). You can try disconnecting the fuel lines and spraying them out with cleaner to remove any sitting sludge as well. Replacing the fuel filter is also recommended if the carburetor is showing signs of contamination. If the lawn mower has a gas cap vent, open it to clear any visible clogs. If none of these steps solve the problem, it’s worth having the carburetor replaced by a pro.

The spark plugs are worn or damaged

Spark plugs in a lawnmower may only be a small part, but they have a huge impact on how your machine runs. If you find that your lawnmower keeps dying, or keeps stalling while cutting grass, then inspect the spark plugs.

If you have a spark plug tester floating around your garage, then put it to good use. Test it to see if it’s defective or still working. When the engine is cranking, you should notice a spark between the terminals to show that it’s in good working order. If you don’t see a flash, the spark plug is defective.