Lawn Mower Keeps Dying Right After it Starts

This is a frustrating experience when you are ready to cut your lawn and have made the time to do it. All you want to do is pull the cord or turn the key and get that job over with.

In most cases what you are dealing with is a fuel problem. The carburetor is not allowing fuel to pass through one of the jets and it normally is the idle jet. The main jet could also be partially plugged up or is sucking some debris into it from the carburetor float bowl.

A lack of fuel is causing starvation and the engine is dying because of it so you must get to the root of this problem to find out why. This will often require the carburetor to be taken apart and thoroughly cleaned inside and out. The ethanol in the fuel today will leave a powder like residue when it dries up and this will clog those ports. Dipping the carburetor with the plastic removed in Chemdip is one such way to clean them very well.

After you have cleaned up your carburetor, reinstall it and test your engine to see if it cures the problem with it dying right after it starts. If it does not, you may have to replace the carburetor but also check your air filter to ensure that it is not plugged with dirt and debris.

My Lawn Mower Engine Dies After Running a Short Time

These runability problems are tricky at times to troubleshoot. Did I put good gas in the mower? Is the ignition system working properly?

Those are a couple of things that we automatically think of when our lawn mower is not working like it should. It can be frustrating to deal with those things and they must be figured out one by one.

Troubleshooting is a process of elimination. Those words alone tell so much about how to look at this problem by eliminating what it is not.

The first and easy step is to make sure there is enough gas in the tank. If that checks out fine, then move along to the next item like the ignition system. Install a spark tester and start the engine. Run it at full throttle for a while and see if at any point that the spark tends to die out. If so, there is something wrong in the ignition system. You should also change your spark plug just to eliminate that. Spark plugs are cheap so change it out.

Fuel delivery is another problem that can cause the engine to die. Is the carburetor getting the fuel it needs to run? Inspect the fuel system for blockages and such as the in tank or inline fuel filter and the carburetor itself.

By systematically eliminating these things, you will find the problem quickly. If you need professional lawn mower repair assistance, visit our Locations page for help.

My Lawn Mower Backfires and Then Dies

The first thing you must find out is if it backfires through the exhaust or the intake or carburetor side of the engine. In a lot of cases it will be on the intake side of the engine. When it backfires, it is sending out raw fuel out the carburetor and the ignition is igniting it and you may see flames come through the air filter or it blows off the air filter box completely. When it blows the fuel out, the combustion chamber has no fuel left in or very little and the engine dies. The same thing can happen in the exhaust.

So obviously we have a timing problem or a valve problem. A set of tests must be done to determine what the problem is. The first test is a leak down test. This will tell you if your valves are leaking and which one is the culprit. It could be both of them causing the problem.

Checking the engines timing is more difficult and requires that the engine be taken apart to see if the timing gear cam or chain has jumped a tooth. But before you go ripping things apart, check the flywheel key to make sure that it is not partially sheered. One some models you have to remove the flywheel to check it, but on most you remove the nut holding it in place and you will see it.

These tests are often out of reach for many home owners because they do not have the test equipment. Check our Locations page for a shop near you for help.


Lawn Mower Seems to Run out of Gas

You are mowing along and the next thing you know the mower seems to run out of power and slowly dies. It doesn’t die quickly, it just powers down and then quits.

This problem is not that uncommon for lawn mowers and there are various reasons why a lawn mower would run out of gas. For instance, your gas cap may not be venting or a fuel filter may be clogged with debris. A fuel line could be collapsing or have debris in it.

The easy test it to run the engine with the gas cap loosened a little so air can come through the threads. If the engine still stalls out, then the problem lies elsewhere. Replacing the fuel filter will help eliminate that and from there you need to check out the other fuel related components to see if they are working properly.

If you cannot find the source of the problem, visit our locations page and see if there is a lawn mower repair professional in your area that can resolve this problem.

By testing each component, you can resolve the issue of the lawn mower seems to run out of gas.

My Lawn Mower Dies After Starting

This is one of the most common things that happens to a lawn mower. You pull the rope or turn the key and it starts and then dies quickly. It may run for a few seconds or less than a minute and then it dies as if you flipped a switch.

It almost always turns out to be a fuel problem that is causing this issue or more specifically, not getting enough fuel.

If your lawn mower dies after starting, the first thing you want to do is remove the gas cap and listen for a vacuum type sound. Kind of like when you pull the tab on a can of pringles.  If you hear that vacuum sucking sound, the gas cap vent is not working and it needs to be replaced.

If the gas cap is not the problem, you could have stale fuel or water in the fuel. A fuel sample should be taken from the fuel line going to the carburetor. Pinch off the fuel line and then disconnect it from the carburetor. Then allow fuel to flow into a small glass jar and if you see water collecting or the fuel is cloudy, it is bad.

If the fuel is good, then the problem most likely is in the carburetor and it will need to be removed and thoroughly cleaned. After cleaning the carburetor, re-install it and then start the lawn mower.

If it runs better but is now surging up and down, then the carburetor still requires cleaning and pay particular attention to the main and idle jets. Also be sure that your carburetor gaskets are good and that the bolts are tight holding the carburetor on.

Other things can cause your lawn mower to start and then die, but in most cases the fuel is the problem and is a problem that can be solved.

My Lawn Mower Dies After Starting

This is one of the most common problems you can have in the early spring when you pull out the lawn mower for the first time. The mower will run for a few seconds and then it will die as if you shut off a switch.

Most of the time this is caused by not using a fuel stabilizer like Ethanol Shield  or Stabil . When your gasoline or diesel fuel is stabilized, it prevents the fuel from phase separating into different parts and then drying up while inside of a carburetor or fuel injected mower. Once dried up, they plug up those vital ports that allow the engine to continue to run. Just enough fuel will enter the engine to start but the full throttle it needs to run will happen because the engine is starving for fuel.

The carburetor will need disassembled to clean all the ports properly. In some cases you can remove the float bowl screw at the bottom of the bowl and clean out the main jet that is in that screw. On Chinese and Japanese lawn mower engines, the idle jet must be cleaned in addition to the main jet and emulsion tube which is inside the fuel tower that runs vertically through the carburetor.  The idle jet is located inside a plastic plug that is held in place by the idle speed control screw that is also plastic. The idle jet has a very small port size so use something like one strand of wire from a small electrical wire.

Use carburetor cleaner to spray out all the ports and then blow them out with low pressure compressed air. Re-assemble the carburetor and install and test to see if it works as it should. It is runs but surges, you still have a blockage somewhere in the carburetor that will need to be cleaned. Repeat the process until you find that port that is blocked. You could also have an air leak and may not have the bolts that hold the carburetor tight enough.

Make sure you have fresh fuel in the engine as well because stale fuel will not light off very well or produce the power you need to keep the engine running. By cleaning your carburetor, you will fix the problem of my lawn mower dies after starting.

My Lawn Mower Will Not Stay Running

This is another frequent problem with a lawn mower. It will run for a while and then dies. It could run for a few seconds or it could run for 30 minutes and decide to conk out. It really doesn’t matter to you of course as you want it to keep on running!

A few things you can check is to make sure your fuel is good. Your mower needs clean and fresh fuel to run. If you can take a fuel sample, it should be clear, not have any discoloration other than a slight yellowish color and not have any debris or particles in it. The odor should be strong and not stale.

If you determine that your gas is bad, it will need to be removed from the carburetor and the fuel tank and fresh fuel added.

Another problem is a carburetor that is plugged up. It will run on choke but when it transitions to the main jet, it will stumble and die because it is not getting fuel through that jet. Cleaning the carburetor is the solution for this problem.

Your choke could be stuck closed and cause the mower to run for a short period of time and then die. You can tell this by looking at the open end of the carburetor and seeing if the butterfly is closed or if it is opening as the engine warms up. A stuck choke will cause your lawn mower to not stay running every time.

The last thing is the ignition system. Your ignition coil could be heating up and malfunctioning. When an ignition coil breaks down, it will stop producing power to the spark plug and it will die at that point.

By checking these items one by one, you can narrow down what the problem is and get your lawn mower running once again.