Lawn & Garden

Solved! Why Does My Lawn Mower Keep Dying?

There are few things more frustrating than when you’re trying to mow the grass and the lawn mower keeps dying. Luckily, there are a few causes that you can troubleshoot without having to buy a brand-new mower.
Melissa Graham Avatar
Lawn Mower Keep Dying

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Q: I’ve tried to mow my lawn multiple times this week, but the lawn mower keeps dying. What could be causing it to stop running? Do I need to call a professional or buy a new mower, or is this something I can fix myself? 

A: Your mowing shoes are on, you’ve put on sunscreen, and you’re ready to tackle your overgrown yard. But instead of hearing the smooth sound of the engine running, the mower sputters to a stop. When a lawn mower keeps dying, it can prevent a homeowner from doing the necessary work to maintain the home’s curb appeal. The good news is that lawn mower repair can often be a DIY project. From how to clean a lawn mower carburetor to replacing a lawn mower’s battery, the steps below can help solve almost any lawn mower problems.

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For those who lack DIY experience and would rather leave the repairs to a professional, one of the best lawn mower repair services will know why a lawn mower won’t start and how to solve the problem so it springs back to life.

Dirty carburetorEngine won’t start, sneezing or popping sounds, black smoke, leaking fuel
Old or bad gasolineRough idling or stalling, pinging sound, gas smells sour
Dirty spark plugHarder tugging on rewind required, gas running out quickly, engine turning over but not starting
Excess oilWhite smoke, overheating engine, slow starts
Clogged fuel cap ventEngine sputtering or misfiring

A dirty carburetor or clogged carburetor bowl could cause a lawn mower to stop running.

Lawn Mower Keep Dying

If a lawn mower won’t stay running, a dirty or clogged carburetor could be the culprit. A carburetor mixes the air and fuel in the mower to create internal combustion. If the bowl gets clogged or fuel residue affects the inlet or outlet ports, the motor could stop running. Clogged carburetors also tend to result in the production of black smoke or sneezing and popping noises.

To resolve this problem, it’s possible to disconnect the fuel lines and apply a carburetor cleaner to get rid of any leftover slime from old fuel.

Old gasoline needs to be changed for the lawn mower to run properly. 

When a lawn mower sits dormant for months without use, old fuel can evaporate and leave a sticky residue that prevents the mower from running properly. Old gasoline will also have a sour smell. If the lawn mower starts and then dies frequently, it may be necessary to drain the old fuel out of the tank and clean off carburetor ports before adding new fuel. This is especially true for mowers in cold climates, when conditions can lead to condensation inside the fuel tank.

Dirty or defective spark plugs can cause a lawn mower to stop working.

A spark plug ignites the fuel in the lawn mower’s engine, which is why a dirty or defective spark plug could be the reason a mower keeps dying. If the engine is turning over quickly but not starting, the lawn mower sounds weak, or it seems harder to pull the rewind on the mower, the spark plugs may be dirty or defective.

It’s first necessary to find and inspect the spark plug, which is typically positioned on the front of the mower. Here, it’s possible to see if the electrode and insulator have accumulated any buildup or become disconnected. If the plug is dirty, it needs to be disconnected and cleaned with a wire brush and specific spark plug cleaner. (Even if the spark plug doesn’t show significant buildup, it’s still wise to clean it.) The spark plug will then need to be reconnected to see if the mower starts and stays running. If the mower continues to die, it may need a new spark plug altogether.

Lawn Mower Keep Dying

Too much oil in the reservoir can cause lawn mower problems. 

Even the best lawn mowers can experience issues if there’s too much oil in the reservoir. Excess oil in a lawn mower can force the engine to produce more heat, which could lead to the machine overheating. If the lawn mower is blowing white smoke after it’s started, that’s a good indication that there’s too much oil in the reservoir, and a lawn mower that stops running when it’s hot outside could be overheating from an overfull reservoir. Too much oil can also affect the crankcase by causing the oil sump to overflow and causing the crankcase to malfunction.

This issue can be resolved by unscrewing the oil tube and tilting the lawn mower on its side to release the excess oil into a container. At this point, it’s also best to change the oil filter after removing the oil to make sure it’s free from clogs. For those wary of troubleshooting a lawn mower, a lawn mower repair service can check out the machine and help with anything from riding lawn mower repairs to tips on regular maintenance.

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A clogged fuel cap vent can make a lawn mower die. 

A majority of mowers have a vented fuel cap that helps release pressure in the machine and allows fuel to flow from the gas tank to the carburetor. If the fuel cap vent becomes blocked or clogged, it could lead to excess gas fumes inside the mower, which stops the flow of fuel and could be why the lawn mower keeps dying. A needle or pin can be used to poke out any blockages from the breather hole. If the cap has any damage, it’s likely easier to buy a new cap altogether.

Lawn Mower Keep Dying

A professional repair service can solve any type of lawn mower problem.

When all of the options have been exhausted and you’re tired of tinkering with the mower, it may be time to throw in the towel and call a professional. The best lawn mower repair professionals have the skills and experience to identify problems right away and can often fix them on the spot so homeowners don’t have to keep running to the hardware store. The mower may also be experiencing an issue that only a professional can address, which is especially true if there is black smoke coming from the mower or if the mower starts vibrating or shaking once started.

Lawn mower maintenance can keep the mower running smoothly. 

As with any appliance or machine, regular maintenance ensures a mower is in mint condition and won’t experience the many problems that can come with neglect. Regularly cleaning debris from air filters and mowing decks, removing any old gas from the tank, and replacing the battery when needed are all good practices to keep in place when it comes to lawn mower maintenance. The more a mower is taken care of, the less likely a homeowner is to experience issues such as a stalling lawn mower or lawn mower chugging.