Why Your Push Mower Starts Then Dies (13 Reasons)

My son was out push-mowing his lawn when it died. This was his second attempt at mowing his front yard before he gave up out of frustration because he couldn’t keep his mower running.

A few days later he mentioned the problem he was having with his mower. I went through the troubleshooting steps to get his mower running again.

A push mower may start and then die due to a lack of fuel, air, or spark due to plugged filters, bad fuel, a dirty carburetor, a clogged fuel system, a bad spark plug, or a faulty ignition coil. An insufficient engine oil level and plugged mower deck can also cause a push mower to die.

I have put together a list of causes that can be the reason your push mower shuts down. Read on for more information and how to fix your mower’s running problem.

13 Reasons Your Push Mower Dies After Running

Push Mower Gas Tank is Empty

I have to mention an empty gas tank as a reason your push mower can die because it’s the most obvious reason. When you run out of gas, your mower will not run. Now, let’s move on to the other less obvious reasons.

Solution: Add fresh fuel to your push mower.

Bad Fuel in Your Push Mower

When gas sits around in your fuel tank, it can begin to gum up and clog your push mower’s fuel system. Ethanol is in most unleaded gasoline on the market today. The gasoline mixture begins to break down and becomes less effective after about 30 days.

The ethanol added to gasoline attracts moisture from the air. When this ethanol and moisture mixture begins to evaporate, it leaves behind a gummy substance that can cause your push mower to die while running.

Because gasoline has such a short shelf life it’s important to follow these tips to get the best fuel results:

• Use your fuel within 30 days and only buy from busy gas stations
• Don’t leave your gas outdoors where it can attract moisture
• Store gas in a dry place
• Only buy enough gas you can use within 30 days. If you purchase more than this, add a fuel additive to stabilize your gas. I use a product called Sea Foam Motor Treatment. Learn more about its advantages here.

Solution: Drain your gas tank into a container to be disposed of properly. Add fresh fuel with a fuel additive to stabilize and clean your fuel system.

Wrong Fuel in Your Push Mower

With so many types of fuel on the market today, it can be important to know what you need to look for when buying gasoline. Read the label on the fuel tank to know what is in your gasoline.

A push mower uses unleaded gasoline with a minimum octane rating of 87 and a maximum ethanol content of 10%.

This type of fuel is often sold as Regular or E10 gasoline. Remember to read the label to ensure you select the right gasoline. It’s important to note most push mowers sold today are 4-stroke, also known as 4-cycle, engines, and use unleaded gasoline.

If you are using an older push mower, your mower may use a 2-stroke, also known as 2-cycle, engine. This type of engine requires the use of a gasoline and oil fuel mixture. Refer to your owner’s manual for the correct gasoline-to-oil fuel mix ratio.

It’s important to use the correct fuel for your push mower. Failure to do so can result in having to replace your push mower. To learn more about the type of gasoline to use in your push mower, check out my article here.

Solution: Drain your fuel tank and fill it with fresh fuel treated with a fuel stabilizer and cleaner.

Dirty Carburetor on Your Push Mower

A dirty carburetor may gum up and prevent the carburetor from allowing the right amount of gas and air needed to create a combustion in your engine’s cylinder. Your push mower may run sluggish and shut down when the engine is no longer able to get the air and fuel it requires.

Solution: Clean your carburetor to remove gummy deposits and crusty buildups that remain from running old fuel and fuels with ethanol.

You can find instructions to clean your push mower’s carburetor in this guide. If your carburetor is excessively dirty or has broken components, you may have to rebuild or replace it.

Bad Fuel Pump on Your Push Mower

Your push mower may use a fuel pump. A fuel pump is required when the carburetor sits higher than the gas tank. The pump’s function is the push fuel up to the carburetor.

You may be able to tell your fuel pump is bad when it is leaking fuel or it is cracked. When your pump is no longer sealed, it is unable to build the pressure it needs to pump fuel.

Other times you’ll have to isolate your fuel pump being the problem. Check to make sure you are getting fuel to the inlet port on your fuel pump.

Once this is confirmed, remove the fuel hose from your carburetor, start your mower, and check for a consistent or pulsating fuel flow out of the tube. If you are not getting fuel flow, your fuel pump is most likely the problem.

Solution: Replace your fuel pump if you are not seeing a steady or pulsating flow of gas from the outlet port on your push mower’s fuel pump.

Plugged Push Mower Fuel Filter

Some push mowers may use an inline fuel filter. This is a small filter that may be found attached to your fuel line and can become clogged. This prevents your engine from getting the fuel it needs so it may die while running.

Solution: Replace a dirty fuel filter.

Blockage in Your Push Mower Fuel Lines 

You may have found the reason your push mower dies is that it isn’t getting fuel. This may be due to a clog in your fuel lines.

When the lines get plugged, you need to locate the restriction in your lines and remove it. Use fuel clamps to start and stop fuel so you can identify if you have a fuel line clog.

Solution: To clear the line, remove the fuel line and spray some carburetor cleaner in the hose to help loosen the clog. Next, blow air through the line using compressed air until the clog is removed.

Reinstall the line. If you can’t get the clog removed or you find your fuel lines are dry and cracked, you can easily replace it with a new fuel line purchased on Amazon or your local hardware store.  

Bad Push Mower Gas Cap

A push mower gas cap has a vent to allow air to pass through the cap. When this vent becomes plugged, your fuel tank acts like a vacuum and doesn’t fuel to flow out of the tank. Without fuel, your push mower will no longer run.

You may be able to determine a bad gas cap by removing the cap and checking to see if it runs. If it does run well, replace your cap while letting it continue to run. Your cap may be bad if your lawn mower dies with the cap replaced and then restarts with the cap removed.

Solution: If you are unable to unclog the vent by cleaning, you need to purchase a new gas cap.

Plugged Push Mower Air Filter  

Your engine requires air to run. If not regularly cleaned, your air filter can become plugged preventing airflow. Without air, your push mower will shut down and die.

Your air filter should be frequently checked, cleaned or replaced. If left neglected, the lack of air can cause significant engine damage.

Solution: Clean your paper air filter by removing it from the air filter housing. Knock as much dirt out of your filter as possible by tapping it against a hard surface.

Check to ensure you can see light through the paper filter by holding it up to a light. If you can see light through the paper element, you can reuse the filter. If you can’t see light through the paper, it is time to replace your air filter with a new one.

If you are using a foam filter, remove the filter and clean it with mild dish soap and water. Rinse thoroughly and lay flat to dry. Once your filter is completely dry, lightly coat your filter with filter oil and place it in your air filter housing.

Bad or Dirty Poulan Pro Spark Plug

Running faulty or dirty spark plugs on your push mower is another reason your mower can stop running. Your spark plugs may have been able to produce enough spark to start your mower, but it isn’t able to keep it running.

Remove your spark plug and check its condition. A dirty plug that has carbon buildup can cause your plugs to foul out causing intermittent running problems.

Solution: You can attempt to clean your spark plug, however an excessively dark or damaged spark plug must be replaced.

For future reference, it is a good idea to change your spark plug annually when completing your Poulan Pro lawn mower service to reduce your likelihood of running problems due to a spark plug.

Before you move on to checking another potential cause for your push mower dying while mowing, make sure your spark plug wires are secure and your spark plugs are gapped according to your engine manufacturer’s specifications.

Bad Ignition Coil on Your Push Mower

A bad ignition coil can cause your mower to die once it gets hot. The windings on the coil separate and short out. When this happens, the spark plugs are unable to get the voltage needed to work properly.

Solution: Identify a bad ignition coil using an ohm meter to check for a break in continuity. If you find a break, replace the coil.

Insufficient Engine Oil Level in Your Push Mower

Too much oil or too little oil in your push mower can cause your engine to die while mowing. This can cause significant internal damage causing your mower to overheat and die. It may be so significant you will have to replace your push mower’s engine.

Read more about the effects of too much oil in your push mower and the effects of running too little oil in my articles:

This is What Happens with Too Much Oil in a Lawn Mower

7 Things That Can Cause a Mower to Overheat

Solution: Perform your engine oil change according to your push mower’s recommendations. Always fill oil to the correct oil fill levels. If your engine fails to run after correcting your engine oil level, you will need a small engine technician to perform tests on your engine.

Depending on the age and cost of your push mower, it may be best to just replace your mower instead of paying the labor bill to find out what repairs you need to make to get your push mower engine running. Labor rates can cost between $45 and $100 per hour.

Plugged Push Mower Deck or a Dull Blade

Running your push mower with a plugged mower deck causes your engine to work harder when turning the mower blade through the debris buildup under the deck.

Additionally, dull mower blades can put more draw on your engine. This can cause your engine to overheat causing your push mower to die while under load.

Solution: Scrape your mower deck to remove all debris buildup and sharpen your mower blade.