17 Cub Cadet Starting Problems and Possible Fixes

Cub Cadet Starting Problems

Like any machine, you want your Cub Cadet mower to work to get you through a mowing session. Unfortunately, that cannot happen if your lawnmower won’t start, which can be frustrating.

Several Cub Cadet starting problems can affect your machine and keep it from performing its role.

But knowing these problems can help you find a solution and restore your lawnmower to its desired working order.

This write-up presents a detailed rundown of the common problems likely to prevent your Cub Cadet mower from starting.

You also find the recommended solutions for each problem to help you through it.

Why Does Cub Cadet Mower Not Start?

Your Cub Cadet Mower may not start due to;

  • Battery problem
  • Spark plug malfunction
  • Clogged air or fuel filter
  • Faulty charging system
  • Defective switches
  • Dirty carburetor
  • Empty gas tank
  • Bad fuel

Thankfully, each of these problems has a solution. And that is where this detailed guide comes in.

1. Faulty Spark Plug

The spark plug on your Cub Cadet mowing vehicle helps start the engine by producing an electric beam responsible for igniting the combustion.

Without this ignition, you won’t have any combustion; the engine will be unable to burn the fuel and run. This underscores just how crucial this tiny component is.

Unfortunately, a carbon buildup can coat the plug and make it unable to produce the required spark. It can also be damaged or have a loose connection.

Any of these faults affecting its ability to function will make the engine not start.

Possible Solution

Start by inspecting your mower’s bad spark plug connection to determine the exact issue. If a loose connection is responsible, you should notice the spark plug wire is not making the desired connection.

Also, refer to your lawnmower’s engine manufacturer manual for information on gapping the plug. This information should specify the correct way of gapping the spark plug so you can do it correctly.

You will want to use a feeler gauge for gapping the spark plug correctly. Finally, check the component for any noticeable oil or carbon buildup.

If any of these substances covers the tip, it can prevent the spark plug from working properly, leading the engine to misfire.

If you establish that the spark plug is damaged, such a problem will not be reparable. So your only solution is to get a new one for a replacement.

2. Empty Gas Tank

You cannot operate your vehicle without fuel. An empty gas tank means your mowing vehicle will not have the required fuel to ignite, start and run the engine. Any attempts at starting the engine will therefore be futile.

What to do

The solution to this problem may be obvious, but you may be surprised how easily you forget to check your gas level before kicking your mower into action.

So, check your Cub Cadet lawn mower’s gas tank to ensure it has the required fuel. Otherwise, get a refill to make it run.

If you are using gasoline, ensure the ethanol level in the fuel is not greater than 10 percent.

3. Bad Fuel in the Gas Tank

The fuel you put in your mower is unstable and begins to deteriorate after only a few weeks. After about 30 days, this gas has broken down and become almost completely ineffective.

So if you have old gas in your mower’s tank, it will unlikely support combustion, and your engine won’t start.

If you use gasoline, the ethanol in its formula will attract moisture as the fuel degrades. As a result, the ethanol in the degrading gasoline will settle at the bottom of the gas tank, where it forms a gummy substance.

This gummy thing typically clogs the fuel system as the water evaporates.


If your gas tank has degraded fuel, drain it out, and empty the fuel tank. Use a gas siphon pump for this task.

Once done, refill the tank with fresh fuel with a stabilizer added to eliminate the moisture from your system and keep the fuel sound.

You can purchase gasoline with a stabilizer and cleaner already or buy the product separately and add it to your fuel.

For example, you could use Dry gas or Sea Foam Motor Treatment as additives to stabilize your gasoline.

These additives are especially useful when storing the fuel for extended periods as they’ll help keep it from decomposing.

4. Dirty Carburetor

One of the components most affected by old, decomposing fuel is the carburetor. Since this component regulates the amount of fuel mixing with air for combustion in the engine, bad fuel affects it directly.

Decomposing fuel leaves a gummy residue that spreads to the fuel hoses, filters, and carburetor.

Over time, these crusty deposits can build up in the carburetor, inhibiting its ability to perform its role.

Not regulating fuel and air entering the engine may spell doom for your Cub Cadet mower. The engine can run with difficulty or fail to start entirely.

What to do

You can fix this problem by taking the carburetor apart and cleaning it. However, this requires some mechanical skills and the ability to handle small parts.

If you are not confident about handling the work, take it to a repair shop for cleanup. The latter step will allow you to receive expert assessment and advice on whether you need a new carburetor.

5. Blocked Fuel Cap Vent

The vent on your mower’s gas cap connects to a hose that allows air into the gas tank. This provides an essential pathway for air to exit the gas tank when fuel is added and enter when fuel is drawn out.

When the buildup of residues blocks this vent, a vacuum results in the Cub Cadet mower’s gas tank, preventing the fuel from coming out.

When gas is trapped in the tank, the engine cannot receive it, resulting in no combustion.

What to do

Check if the gas cap vent is the culprit by removing the fuel cap and starting the vehicle.

If your mower starts successfully, reinstall the gas cap while the mower is still running. Observe and see if it dies after reinstalling the fuel cap.

If this happens, it confirms that the gas cap is indeed responsible for cutting the fuel delivery into the engine.

After confirming that the fuel cap is the problem, replace it with a new one to fix the problem.

6. Loose Battery Terminals

Like any vehicle with a gas engine, a Cub Cadet lawnmower uses the energy from a battery to start.

This requires connecting the positive cable from the vehicle to the positive terminal of the battery and the negative cable to the battery’s negative terminal.

You must tighten these terminals connecting them to secure the cables and allow for a steady flow of electrical current.

If any terminal has a loose connection, it will create an unsteady current flow or break it altogether.

As a result, the mower’s electrical systems will not receive the current they require to ignite the engine. Therefore, the mower will start sluggishly or fail to start completely.


Check both the red and black terminals to identify the loose connection. Tightening the bolt in the suspect terminal should help secure the terminal and re-establish the proper flow of electric current.

7. Bad Battery

A bad battery can have corroded terminals or some other mechanical fault. Any of these will cause your Cub Cadet lawn mower not to start.

If one or both of the battery terminals are corroded, the buildup can prevent the connection from being complete.

An incomplete connection breaks the flow of electric current to the systems requiring it to power the engine.

The battery must also hold a charge of not less than 12.7 volts to power the Cub Cadet lawn mower.

If the battery cannot hold the charge, it will be unable to power the mower, and the engine may not start.

What to do

Start by testing your lawnmower’s battery using a multimeter. What you need is a reading of not less than 12.7 volts.

If the display indicates fewer volts, consider recharging the battery before testing it again. After a full recharge, retest the battery with a multimeter to see if it reaches the desired voltage.

If the reading is still less than 12.7 volts, the battery has probably degraded from years of use and requires a replacement.

Replacing a battery that no longer holds a charge should help fix the problem.

8. Failing Fuel Pump

The fuel pump is a component that directs the gas into the carburettor. The tank is often located below the carburetor and depends on the pump to move the fuel up.

If this pump malfunctions, the carburetor will not be able to draw the fuel from the vehicle’s gas tank. This means your mower cannot use the fuel even with a full tank of gas.

Such malfunctions can result from prolonged use of old fuel that degrades and clogs the essential components of the pump.

Recommended solution

Start by pinpointing the exact fault in the fuel pump. You can do so by visually inspecting the mower’s vacuum gas pump for leaks and cracks.

Any traces of fuel outside of the pump will indicate leaks from cracks in the gas pump. Such cracks render the pump unable to get fuel to the carburetor using pressure from your crankcase.

Next, start and stop the flow of gas from the tank to the pump using your vehicle’s fuel shutoff valve. This should help you determine if the pump is getting fuel via the shutoff valve.

Otherwise, the fuel filter or hoses may restrict the flow. You will need to check them to determine which point is causing the restriction.

However, if the fuel flow into the pump is steady, the fuel pump is the likely culprit. Still, you want to observe its outflow to be certain.

So, stop the gas flow and remove the hose from your carburetor. Next, place the fuel hose in a container and start the fuel flow and the lawnmower.

Once the mower is running, observe how the fuel flows into the container. A consistent pulse will mean the gas pump is working all right.

A bad, inconsistent fuel flow into the container will indicate a faulty pump. The solution for a bad fuel pump is to replace it with a new one.

9. Clogged Fuel Line

As already mentioned, using old fuel in Cub Cadet mowers leads to the accumulation of residue that can clog the mowers’ fuel delivery system.

The fuel line is one of the primary victims of these residues, getting blocked by dirt and gummy deposits from bad fuel.


Pull out the fuel line and clean it by spraying a carburetor cleaner into it to loosen the accumulated deposits.

Also, you will want to blow compressed air through the affected hose to push out the blockage. You can replace the line if you believe it is in bad shape.

10. Clogged Cub Cadet Fuel Filter

Fuel lines connect the mower’s fuel tank to the carburetor, transferring the gas from the tank to the engine.

The fuel passes through the filter located between this tank and the gas pump. Since the filter removes contaminants and impurities from the gas, it receives the most impact from bad fuel.

Bad, old fuel has lots of impurities that clog the fuel filter over time. Such a blockage will cut the engine’s supply of gas, leading to its failure.

Fixing the filter problem should help restore the disrupted fuel supply to the engine and restore normal starting and running.

What to do

A damaged fuel filter will mean the fuel running into it does not come out. So, replace such a filter with a new fuel filter and allow your Cub Cadet to start and run normally.

11. Faulty Safety Switch

Your Cub Cadet lawnmower has safety switches intended to keep you safe by killing the engine when you leave the mower’s seat.

Any safety switch malfunctioning may send a wrong signal, keeping the mower from starting. Such a malfunction may involve not detecting when you are on the seat or out.


A quick fix for this problem is to bypass the safety component temporarily. This will allow you to identify which switch has malfunctioned.

Once you identify the faulty safety switch, replace it before resuming operations. You don’t want to operate the machine without a safety switch installed.

The purpose of the safety switch is to guarantee your safety, so a malfunction or total absence of one potentially puts you in danger.

12. Bad Ignition Coil

The ignition coil in your mower is responsible for channeling the required electrical current to the spark plug, which in turn creates the electrical beam needed to ignite the engine.

If this coil malfunctions, the spark plug will be unable to ignite the engine, leading to a misfire and failed start.


Use an ohmmeter to check the flow of current through the faulty ignition coil. If you detect a broken flow in the electric current, get a new ignition coil to replace the bad one.

13. Bad Ignition Switch

The ignition switch is where you insert the key to start your engine. If nothing happens when you turn the key, you might be staring at a faulty ignition switch.

What to do

Test the suspect switch with a multimeter. If it turns out not to work as required, install a replacement to fix the problem.

14. Incorrect Starting Procedure

Starting your Cub Cadet lawn tractor requires following a standard operating procedure. These procedures are designed to ensure proper operation and your safety while using the mowing vehicle.

The safety features in your mower will therefore prevent the engine from starting if you fail to follow these procedures.

What to do

The solution to this problem is detailed in your mower’s operating manual. Refer to the manual and strictly follow the correct steps as detailed in the document to start and operate the mower.

15. Faulty Charging System

A defective charging system may not directly prevent the mower from starting, but it can do so through the battery.

Your mower’s ignition system requires a charged battery with at least 12.7 volts to ignite. If the malfunctioning charging system creates a weak battery, the mowing vehicle won’t start.

What to do

Get a technician to help you identify the malfunction and recommend a fix.

You want to avoid replacing parts of such an elaborate system as this might mean unnecessary costs on replacing otherwise sound parts.

16. Starter Solenoid Malfunction

As the name suggests, the starter solenoid starts the engine. So, naturally, the mower won’t start if this component fails to perform its role.

This electromagnetic switch activates the starter motor, which turns on the mower’s engine. You can tell if it malfunctions by hearing a hum or a click when you turn the ignition key.

Alternatively, the cable attached to the starter solenoid may get hot and start melting or producing smoke. This is a common problem with Cub Cadet XT1.


Refer to your operator manual and follow the procedure given to test the solenoid. If the test indicates that it is bad, get a new one to replace it.

17. Plugged Air Filter

Your lawnmower’s engine uses oxygen from the air for its combustion. This means the engine must get a good supply of air to run.

Clogged air filters can inhibit the engine’s air supply. If this blockage is serious, the amount of oxygen reaching the engine may not be enough to ignite it. This will likely lead to a failed start.

Clogged air filters can also cause significant damage to the engine, starting with overheating.

Recommended fix

Start by carefully removing the paper air filter from its housing and tap it gently against a hard surface to extricate the dirt and debris.

Using an air compressor to clean the filter is not recommended. The pressure will only do more damage instead of fixing the problem.

You must be careful when removing the air filter, so you do not drop any loose debris and dirt into the vehicle’s air intake.

Once done, hold the filter against a light source to see if the light passes through it. If yes, wipe the housing to remove any remaining dirt and return the filer.

If no light passes through the filter after knocking out the dirt, replace it with a new one.


What would cause a Cub Cadet lawn mower not to start?

A clogged fuel filter would cause a Cub Cadet mower not to start. This problem most commonly results when old fuel stays in the mower for prolonged periods. Over time, the fuel degrades, with some ingredients evaporating and leaving behind a gummy residue.

Why is my lawn mower cranking but not starting?

When a lawnmower cranks but does not start, the most common culprits are often low fuel in the gas tank, a faulty choke, a broken spark plug, or a broken gas valve.

How do you tell if your Cub Cadet solenoid is faulty?

With the ignition key in the “on” position, grab a wrench and lodge it between the two large terminal posts on your solenoid, ensuring it touches each post. These are the two posts where the thick red cables from the starter motor and the battery are bolted to the solenoid. You’ll know the solenoid is bad and needs replacement if the engine turns over and starts.

Why does my lawnmower start up and then quit?

A lawnmower starting and then dying after running for a brief moment may be due to a clogged carburetor, bad fuel in the tank, or faulty spark plugs.

Cub Cadet Starting Problems: Final Thoughts

Many factors can cause your Cub Cadet lawnmower not to start indeed. However, you should be happy to know you can use the solutions in this write-up to fix each.

Admittedly, one or two problems may require the help of a mechanic, but most of the problems are straightforward to fix, and you can get around them on your own.

We hope this post helps solve your Cub Cadet starting problems. Let us know your thoughts in the comments.