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10 Reasons Your Cub Cadet Lawn Mower Won’t Turn Over

You have finally found time in your busy schedule to mow your lawn. You’re happy to be able to get it done and out of the way. However, this time your mower won’t turn over. I have put together a list of items to check when you run into this problem.

A Cub Cadet lawn mower won’t turn over when it is unable to get spark, fuel and air required to create a combustion. This can be due to a bad spark plug, bad battery, dirty carburetor, plugged air filter, bad starter solenoid or clogged fuel components.

Keep reading for more items that can cause your Cub Cadet not to turn over. Make sure you are following all safety precautions as shown in your owner’s manual.

Cub Cadet Mower Won't Turn Over

Why Your Cub Cadet Mower Won’t Turn Over

Dirty or Bad Spark Plug or Loose Spark Plug Wires

When the spark plug fouls out and the tip is dirty with a buildup of carbon and oil, your mower will fail to turn over. If the spark plug can’t produce enough spark, it won’t be able to start the engine.

Remove our spark plug using a 3/4” or 5/8” socket depending on your engine model. Inspect the spark plug for a dirty tip, burnt electrode or cracked porcelain. You can try to clean a dirty spark plug using a wire brush. If the tip is very dark or you find damage to your spark plug, it must be replaced.

Check the spark plug wires. Some refer to these as leads or boots. Make sure they are securely in place and functioning properly.

Dead or Bad Battery in Your Cub Cadet

A dead battery won’t provide the power you need to start your Cub Cadet. Keep your battery charged, especially during storage, to extend your battery’s life. Test your battery using the steps in the article “5 Things That Are Draining the Life of Your Lawn Mower Battery”.

Charging a Battery: Use a battery charger to charge your 12-volt battery. Before you continue, wear protective gear to protect your eyes and skin from electrical shock. Follow these steps to charge your lawn mower battery with a charger:

  • Access the battery and terminals. You may need to use a screwdriver to uncover the battery. Do not remove the battery from the casing.
  • Connect the charging cables beginning with the positive cable first. This is the red cable or the one with the plus sign. Place the cable on the positive battery terminal.
  • Attach the negative cable to the negative battery terminal. This is the black cable or the one with the negative sign.
  • Do not touch anything that doesn’t have a rubber coating to prevent electrocution.
  • Set the charger’s voltage and amperage level to the desired level. The average volt level for lawn mower batteries is usually 12 volts. More amperage charges the battery faster. Start with two camps and work up to no more than 10 amps. A slow charge is best.

If the battery fails to hold a charge it must be replaced with a new battery. You can purchase a new battery at your location lawn mower dealership, hardware store or automotive store. Bring your old battery with you. Most places will charge you a core fee unless you provide them with your old battery.

Loose or Wires and Connections in Your Cub Cadet

Wires and connections can become loose with the constant vibration of your Cub Cadet. Make sure they are secure. While checking the connections, make sure the terminals are free of corrosion.

The outdoor elements can cause moisture around the connections causing corrosions. Try to remove this corrosion using a wire brush and a baking sold solution (2 cups water to 3 heaping tablespoons of baking soda). Replace the terminals if the corrosion is too severe.

Bad Starter Solenoid in Your Cub Cadet

A starter solenoid is an electromagnetic switch that, when engaged, initiates the starter motor to turn over your Cub Cadet’s engine.

The starter solenoid can go bad when the spring becomes weak or the copper plate begins to corrode. A weak starter, bad battery or bad ground can also cause the solenoid to fail.

Before you test your starter solenoid, you must have a fully charged battery. Continue testing the solenoid by using the steps to diagnose a bad starter solenoid in “How to Tell Your Lawn Mower Solenoid is Bad”.

Cub Cadet Air Filter Restriction

When your air filter becomes so plugged your engine isn’t able to get air, it can fail to turn over and start. It’s important to regularly check and clean your air filter to prevent starting issues and engine damage.

Remove your Cub Cadet air filter from the air filter housing. Wipe out any dirt remaining in the housing being careful not to knock any dirt into the air intake. Proceed with the following steps to clean your type of air filter.

Clean Cub Cadet paper air filter element

  • Tap your filter against a hard surface to knock the dirt loose and out of your filter.
  • Hold the filter up to a light source.
  • If the light is not being blocked by filter and you can see light through the paper element, reuse your filter.
  • If you cannot see any light, replace your filter with a new air filter for your Cub Cadet.
  • Reinstall the air filter and secure the housing cover.

Clean Cub Cadet foam air filter element

  • If your filter has dark spots or rips or you notice it is dry and brittle, replace your foam air filter.
  • Clean your filter by washing it with a mild dish detergent to remove dirt. Rinse until the water runs clear and all soap has been removed.
  • Lay flat to dry. Placing in the sun will speed up the drying process.
  • Once dry, add a foam filter oil to the filter.
  • Install the air filter and secure the cover to the housing.

Lack of Fuel or Quality of Fuel in Your Cub Cadet

Check your fuel level. You may not have enough fuel because your mower is consuming more fuel than normal or you have developed a fuel leak. Fill your fuel tank with fresh fuel when you find it is low. Check for leaks or a problem where it is consuming too much fuel.

Gasoline can begin breaking down becoming less effective as soon as 30 days after purchase. The ethanol content in gasoline attracts moisture that can leave a gummy substance behind causing fuel restrictions. When these restrictions form, the engine won’t turn over because it no longer has a supply of fuel.

Make sure you are using the right kind of gasoline in your Cub Cadet and adding a fuel stabilizer when the fuel can’t be consumed quickly. Find out more about the fuel additive I choose to use in my lawn mower here.

Plugged Fuel Filter on Your Cub Cadet Mower

A fuel filter is designed to prevent dirt and contaminants from entering your Cub Cadet mower’s fuel system. Dirty fuel can plug your fuel filter so it is no longer able to pass through the filter.

It is good practice to change your fuel filter annually while performing annual maintenance on your Cub Cadet. Stop the fuel flow before removing the old fuel filter. You can use the fuel shut-off valve or crimp the fuel line if you don’t have a shut-off valve on your model mower.

When installing your new filter, make sure the filter is installed with the arrow on the filter pointed with the fuel flow. This means it needs to be pointed toward your carburetor and away for your fuel tank.

Clogged Fuel Lines on Your Cub Cadet Mower

A fuel restriction can be caused when your fuel lines are clogged and fuel is no longer able to move through the fuel system. This will cause your Cub Cadet not to turn over. Check for a restriction by stopping and starting fuel flow while checking a section of fuel line for flow.

When you find you a section of line with a restriction, remove the fuel line from your Cub Cadet. Spray carburetor cleaner into the line to help loosen the clog.

Follow this by blowing compressed air through the line to remove the blockage. Replace the line with a new fuel line if you are unable to clear the blockage.

Bad Fuel Pump on Your Cub Cadet Mower

Your Cub Cadet may not turn over because your fuel pump is no longer pushing fuel to the carburetor. Check to make sure you are getting fuel to the inlet port of the fuel pump.

Then check to make sure the pump is functioning properly by removing the fuel line from your carburetor and placing it in a container.

Start your mower to make sure your pump is building pressure and pumping fuel to the carburetor. If you have a steady or constant flow coming out of the fuel line you placed in the container, your fuel pump is functioning properly. If not, replace the fuel pump.

Dirty Carburetor on Your Cub Cadet Mower

Old fuel that is stored and ran through your Cub Cadet can clog the fuel jet and gum up other areas of the carburetor causing components to stick. This prevents the engine from turning over and starting because there is a lack of fuel flow.

If you checked for a fuel restriction in your fuel filter, fuel lines and fuel pump, and find you are getting fuel to the carburetor, it is time to proceed with the next step.

Remove the air filter and spray carburetor cleaner into the intake. Start your mower. If it starts, runs and then dies, take your carburetor apart to clean it.

You can find step-by-step instructions to clean the carburetor on your Cub Cadet in this article. If you are a little mechanical, you shouldn’t have any problems cleaning the carburetor yourself. A small engine mechanic can also clean this for you if you don’t feel up to the task.

Still Having Problems with Your Cub Cadet Mower?

If the above list did not resolve your problems, I put together a guide of common mower problems and solutions. You will find links to more in depth articles for each of these common issues. You can find the article at “Common Cub Cadet Lawn Mower Problems”.