When it comes to taking care of your lawn, nothing is more frustrating than a mower dying in the middle of your lawn. If you’re a long-term lawn mower owner, you probably understand what I’m talking about.
If not, owning a mower long enough will make it more likely you will encounter this situation.
A Bad Boy lawn mower starts and then dies when bad fuel clogs the fuel system, a plugged air filter restricts airflow, or a bad spark plug and ignition coil results in a lack of spark. A Bad Boy lawn mower may also stop running due to a plugged mower deck, dirty carburetor, or bad fuel cap.
Keep reading as I share a full list of items that will cause your Bad Boy lawn mower to shut down after mowing. Always take safety precautions as outlined in your owner’s manual. Some of these precautions include:
- Remove the ignition key and spark plug wires when working on your mower.
- Take caution when working around a hot engine.
- Wear eye protection to avoid getting fluids or dirt in your eyes.
- Protect your hands from sharp components.
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Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.
Reasons Your Bad Boy Lawn Mower Starts Then Dies
Bad or Old Fuel
Running gasoline through your gas-powered Bad Boy lawn mower that has been sitting for a long period can cause problems in your fuel system including corrosion and varnish buildup. Most gasolines offered today contains a product called ethanol.
Ethanol is a corn-based alternative fuel added to gasoline to be more environmentally friendly than gasoline. While ethanol may be better for the environment and okay to run in most vehicles, it can create problems in your Bad Boy mower.
Ethanol-based gasoline can begin to break down as soon as 30 days after purchase. This means it becomes less stable and effective.
The ethanol in the fuel attracts moisture from the air. This ethanol and moisture mixture will separate from the gasoline and sink to the bottom of your fuel tank.
Running this solution through your mower can cause engine damage because it burns hot. When this solution evaporates, it forms a gummy substance that creates fuel restrictions by clogging the components like the fuel lines, fuel filter, and carburetor.
When your Bad Boy mower can’t get the fuel it requires to run, it will stop running.
Solution: When you find your fuel is old, drain the fuel tank using a fuel siphon. Refill your tank with fresh fuel. Add a fuel additive to stabilize your fuel, reduce moisture and clean your fuel system.
I use a product called Sea Foam Motor Treatment. Learn more about why I use Sea Foam in every tank of fuel in this guide.
Clogged Air Filter
It’s important to always run your Bad Boy lawn mower with an air filter. The filter is required to prevent dirt and debris from getting to the engine. Dirt particles can cause significant engine damage resulting in a large repair bill.
Your Bad Boy mower requires air to start and run. When airflow is restricted, your mower will die. It’s good practice to replace your air filter annually and regularly clean it throughout the mowing season.
Failing to run a clean air filter will not only cause your engine to run sluggish and shut down, but it can also cause your engine to overheat leading to additional mower damage.
Solution: Clean your air filter by removing it from the air filter housing. Be careful not to let any dirt or debris fall into the air intake. Wipe out any dirt remaining in the housing with a dry cloth. Proceed with the instructions for your air filter type:
Clean Bad Boy Mower Paper Air Filter Element:
- Tap the filter against a solid surface to loosen and remove as much dirt as possible.
- Hold the filter up to a light source to check if you can see light shine through the filter. If you can, go ahead and reuse your air filter. If you cannot, you must purchase a new filter.
- Install the air filter and reinstall the cap on the filter housing.
Clean Bad Boy Mower Foam Filter Element:
- Inspect your filter for brown spots, tears, or a dry brittle condition. If you find any of these items, purchase a new filter for your Bad Boy mower. If your filter is in good condition, proceed with cleaning it.
- Clean your filter with a mild dish detergent and water to remove dirt and any oil residue on the filter.
- Rinse the filter to remove all soap and lay flat to dry.
- Once the filter is dry, use a foam filter oil to coat the filter. You do not want the filter to be dripping with this oil. Wring out any extra oil and replace the filter in your housing. Note: You need to add filter oil to a new air filter. This oil helps prevent dirt from passing through the foam filter.
- Install the air filter and reinstall the cap on the filter housing.
Clogged Fuel Filter
Your Bad Boy mower uses a fuel filter to strain the fuel. It prevents dirt and other contaminants from entering the fuel system. Dirt and gummy deposits from your fuel can plug your fuel filter over time.
It’s best practice to replace your fuel filter annually to avoid most fuel filter issues during the mowing season.
Solution: If you find your fuel filter is plugged, remove it and replace it with a new filter. You will find an arrow on the side of your fuel filter.
Make sure this arrow is pointed in the direction of the mower’s fuel flow. This means a correctly installed fuel filter will point toward the carburetor and away from the fuel tank.
Clogged Fuel Lines
The gummy deposits that are left behind when running old fuel can clog your fuel lines preventing fuel from continuing to run through the fuel system. This can cause your Bad Boy to die while mowing.
Check each section of the fuel line by shutting off your fuel flow using the fuel shut-off valve located at the bottom of your fuel tank. You can also use pinch pliers to crimp the fuel line to stop the flow.
Remove the fuel line from the fuel pump and place it in a container. Start your fuel flow. (Make sure the container is placed lower than the fuel tank because fuel cannot run uphill without the help of the fuel pump. A push mower may not use a fuel pump).
If you find you have sufficient flow into the container, shut off the fuel flow and reattach the fuel line. Proceed with checking other fuel components for a restriction or failure.
Solution: If you do not get good fuel flow from the fuel line into the container, check any sections of the fuel line or the fuel filter that could have the blockage.
Once you isolate the blockage to a specific section of the fuel line, shut off your fuel flow and remove the section of the line from the mower. Spray carburetor cleaner into the line to help loosen the blockage.
Follow this by blowing compressed air through the line to remove it. Repeat as necessary. If you are unable to clear the blockage, replace the line with a new fuel line.
Carburetor is Dirty
The carburetor’s main purpose is to regulate the amount of fuel mixed with air to form a combustion in your engine. When the carburetor doesn’t work properly, your mower can start and then die.
The carburetor becomes dirty from running old fuel that sits in your carburetor causing gummy and hard deposits to form. This can cause components on your carburetor to restrict the flow of fuel.
Solution: Before you tear your carburetor apart, make sure you are getting fuel to the carburetor. Once that is confirmed, remove your air filter and spray carburetor cleaner into the air intake.
Start your mower. If you find it dies after running, disassemble your carburetor and clean it. Follow the steps in this guide to clean your carburetor.
Plugged or Broken Cooling Fins
Your Bad Boy mower can start and then die when your mower’s engine gets hot. Check your engine cooling fins. They may be plugged with debris or broken.
The fins on the flywheel push air around your engine block and cylinder head to keep it cool. Plugged cooling fins can restrict the amount of air circulating around your engine.
Solution: Take caution working around your hot engine. Remove any debris stuck in the cooling fins. Replace any broken fins. Clean debris around your engine and engine shroud. Ensure your heat shield is attached securely.
Insufficient Engine Oil Level
Your mower requires a specific amount of engine oil in the crankcase for the engine to run at its best. Most people know you can develop problems when your engine oil becomes too low, but don’t know you can also have problems if there is too much oil in the crankcase.
Too Much Engine Oil
Next, check the engine oil level in your mower. Too much engine oil in your Bad Boy lawn mower will cause pressure to build in the crankcase.
This can cause your mower to overheat and shut down. Read more about the impact of too much oil in your Bad Boy mower.
Remove some engine oil through the drain plug or oil filter. You can also use an oil evacuator or turkey baster to suck oil through the engine oil fill area.
Check the engine oil level on the dipstick. Continue to add or remove oil until the oil level is at the full line on your dipstick.
Too Little Engine Oil
You may have developed an engine oil leak or have a problem in your engine where it is using or burning oil. When you don’t have enough oil to keep the internal engine parts sufficiently lubricated, friction starts to build creating heat.
This heat can overheat your engine and cause it to die. The heat can be so hot, your internal engine parts will start to melt.
Here’s the bad news: If your engine shuts down because of a lack of engine oil, chances are significant damage was done.
Your best solution here is to take your mower to an experienced small engine mechanic to tear down your engine and perform tests to determine how much damage was done.
Bad or Dirty Spark Plug
A dirty or fouled spark plug on your Bad Boy can cause it to run sluggish and die. Not only will a dirty plug cause this problem, but a plug that is damaged, not properly gapped, or doesn’t securely have the wires attached can cause your mower to stop running.
Solution: Clean your spark plug tip. If you find the tip of your spark plug is very dark, has a burnt electrode, or is damaged, replace your spark plug.
Make sure the plug is gapped following the engine manufacturer’s specifications. Securely attach your spark plug wires. Spark plugs are not very expensive. These should be replaced annually.
Bad Ignition Coil
The winding on the ignition coil can separate and short out when your mower is hot. When this happens, the spark plugs are unable to get the voltage they need to create spark. This can cause your mower to die after it’s been running for a while.
Solution: Identify a bad ignition coil using an ohmmeter to check for a break in continuity. Replace the ignition coil if you find there is a break.
Choke is in the Wrong Position
The choke reduces the amount of air your engine receives. This is used when starting a cold engine to allow more fuel and less air to form combustion in the cylinder.
Solution: The choke lever must be placed in the correct position after the engine is warm to allow additional airflow or the mower will die.
Faulty Gas Cap or Rollover Vents
A gas cap or rollover vent that can no longer vent allowing air to pass to the fuel tank can restrict fuel flow and cause your Bad Boy mower to shut down. When the vent becomes plugged, the fuel tank forms a vacuum not allowing gas to flow to the engine.
Run your mower with and without the cap for periods of time to see if a plugged vent is the cause of your Bad Boy mower dying. If you remove your fuel cap and your mower starts and runs and then replace your cap and your mower eventually shuts off, you may have a problem.
Solution: Your fuel tank may be vented through the gas cap or the rollover vents located on the fuel tanks. Determine which type of fuel tank vent is used on your Bad Boy mower and replace it.
Plugged Mower Deck
A mower deck that is plugged full of debris can cause your Bad Boy lawn mower to shut down. This is because the engine must work harder to turn the blades through a deck full of debris. This can cause your engine to overheat and shut down.
Solution: Prevent this from happening by regularly scraping your deck to keep it clean. Avoid mowing in wet conditions as wet grass clumps and sticks to your mower deck.
You can try using a deck spray to minimize grass buildup. Deck sprays are not a miracle product that prevents all buildup, they can minimize the amount of debris collecting under the deck.
Why is My Bad Boy Lawn Mower Battery Not Charging?
Make sure you are running your Bad Boy mower at a high engine speed. Don’t allow your mower to idle for long periods of time. It requires the power of the engine to charge your battery.
If you continually have to charge your battery and have confirmed the battery and wiring are in good condition and securely attached, you may have a problem with the charging system.
Solution: There are some steps you can take to check the condition of your battery and charging system which I explain in this article. If after performing these tests, you find you have a bad battery, replace your battery.
When you find the charging system isn’t working right, I highly recommend having an experienced mechanic diagnose and repair the problem.
There are so many components that can cause the charging system to fail that, unless you know the charging system, parts can be thrown at it hoping it repairs the issue.
Electrical components can get expensive and they most likely can’t be returned because they are electrical parts.
Still Experiencing Problems with Your Bad Boy Zero Turn Mower?
Own a lawn mower long enough, you’ll start running into problems with it starting, not continuing to run, smoking, leaking gas, giving a bad cut, vibrating, or another issue.
To help you save time and money, I have put together a guide to help you troubleshoot the next problem that develops on your mower.
You can find this guide at Common Bad Boy Lawn Mower Problems & Solutions.
If you are unsure how to perform diagnostics and repairs on your lawn mower safely, it’s best to have a professional complete the repairs.
This will help you avoid personal injury or additional damage to the mower. Your local Bad Boy lawn mower dealership or lawn mower repair shop will be able to help you solve your problem.