Cub Cadet Mower Won’t Start

Cub Cadet Mower Won’t Start (Why + How To Fix)

Cub Cadet is renowned for its high powered lawn and riding mowers and many are comparing the quality to that of John Deere! But even when you use the best brands, things can sometimes go wrong.

If you have found that your Cub Cadet mower won’t start then the reason is likely something you can fix at home. In this guide, we discuss the most common reasons that a Cub Cadet lawn mower won’t start and what you can do to fix the problem.

When you try to start your Cub Cadet lawn mower and aren’t getting anywhere, there are a wealth of issues that could be at play. It might take some time to troubleshoot but it’s worth looking at every aspect in detail to make sure that the problem is solved once and for all.

1. No Gas In The Fuel Tank

This is one of the most obvious reasons that your Cub Cadet mower won’t start and something that a lot of people forget to check. While it might feel like very basic knowledge, it’s surprising how many people take their mowers out of the shed and try to fire them up without even checking if there’s any gas in the tank.

How To Fix It

Take a look to see if there is any fuel in the gas tank. If there isn’t then pop in some fresh 87 octane fuel with an ethanol content over 10%. Never use old fuel as this may also cause problems with your lawn mower starting.

check fuel tank - cub cadet mower

2.Fuel Valve On Your Cub Cadet Mower Is In The Off Position

Within the workings of a gas lawn mower, there is a valve that is designed to stop fuel from going from the tank to the engine. This valve needs to be open to let the fuel through which will give the engine the power it needs to start. If the valve is closed or in the off position, fuel won’t get to the engine rendering the mower useless.

How To Fix It

You will need to locate the fuel valve which is typical near the base of the fuel tank at the point where the fuel line comes into the tank. Check that it is not in the closed position and if it is, open it up. This should solve the problem.

3.Damaged Carburetor

The carburetor, or carb as it is called for short, is a part of your lawn mower responsible for mixing air and fuel in order to create combustion. However, from time to time you may find that the carburetor becomes clogged and this is usually what happens if you leave old fuel in the tank without running the lawn mower.

When you do this, parts of the fuel evaporate and leave behind a thick substance that can clog up several parts of the mower including the carb. When this happens, the part cannot function as normal and so may prevent the engine from starting.

How To Fix It

You can use a carburetor cleaner which is sprayed inside the carb to remove any dirt or blockages. If this doesn’t work then it may be necessary to install a new carburetor.

4.Plugged Up Fuel Filter

Just like the carburetor, it is possible for the fuel filter to become clogged and again, this is most commonly caused when you leave fuel in the lawn mower over a long period of time. Once certain ingredients within the fuel start to evaporate, you’re left with a dense, sticky solution that does no favors to your machine.

How To Fix It

To fix this problem you will first need to remove any old fuel from the tank by draining it. After this, it is highly likely that you’ll have to replace the fuel filter although for those that aren’t severely affected, cleaning may be enough.

5.Bad Or Old Fuel In Your Cub Cadet Mower

We have touched upon the importance of not leaving old fuel in your lawn mower when you aren’t using it for a long period of time and this is a leading cause of why a Cub Cadet lawn mower won’t start.

How To Fix It

You should check the parts of your lawn mower that are most commonly affected by bad fuel; these include the carburetor and the fuel filter as we discussed in the previous sections of this article. If these need to be cleaned or replaced then do this now. Also make sure that you remove any old fuel from the tank and add a fresh batch.

6. Incorrect Operation

When you purchase your Cub Cadet lawn mower, you will notice that it comes with a detailed instruction manual. This includes information on how to correctly start your lawn mower. If you don’t follow these steps to the letter then you may not be able to successfully start your Cub Cadet mower.

How To Fix It

Take the time to thoroughly read through your Cub Cadet lawn mower manual and familiarize yourself with the correct starting procedure. There may be safety switches that need to be used in order to get the mower going so make sure you know how to operate these as well.

7. Blocked Fuel Line On Your Cub Cadet Mower

Earlier we talked about how the carburetor and fuel filter can be affected by old fuel in the tank. Another part of the mower that might suffer when there is old fuel present is the fuel line and this may become blocked. It is also possible for the fuel line to get clogged with general dirt so it’s worth checking it from time to time as part of your mower maintenance. 

How To Fix It

You can clean the fuel line by taking it out and using a carburetor cleaner. You can also make use of compressed air which will blow out any dirt or debris. In some cases, the damage from the blockage may be too much and you might have to replace the fuel line entirely. 

8. Clogged Air Filter

It is essential that your lawn mower has good air flow otherwise there is a risk that the engine will overheat. But even before this has a chance to happen, the engine requires air to get started and if the air filter is blocked, the engine doesn’t get the air it needs. This means that it won’t start.

Overheating occurs when the engine tries to find air elsewhere and it has to work harder so ends up getting too hot. Not only is this dangerous but it can cause serious damage to your engine if left alone.

How To Fix It

The single best way to deal with a clogged air filter is to clean it. A lot of lawn mowers have a paper air filter which you can remove and bang against something solid to remove any dust, dirt, and debris. Afterwards, hold the filter towards the light and see if light passes through. If it doesn’t, the filter is still clogged and may need to be replaced. 

9. Bad Ignition Coil

Your Cub Cadet lawn mower has an ignition coil whose job it is to send voltage to the spark plug. But if the ignition coil isn’t working then there’s a high chance of the engine not starting.

How To Fix It

Your first instinct may be to replace the ignition coil and this will solve the problem in a lot of cases. But it might be an issue with the spark plug so before you do anything, check the spark plug to see if it is working correctly.

If there are no problems with the spark plug then get your hands on an ignition coil tester and test the ignition coil. If there is a problem, you can install a new one.

10. Damaged Recoil On Your Cub Cadet Mower

Gas lawn mowers, including those made by Cub Cadet, have a recoil starter which is used to engage the crankshaft in order to get the engine to turn over. But sometimes, this recoil starter assembly fails and your mower’s engine just won’t fire up.

How To Fix It

To understand whether a recoil starter needs to be replaced, you need to understand how it works. These parts feature a rope which you pull and as this happens, tabs extend from the pulley and cam and then attach to the engine hub. Once you let go of the rope, those tabs come back in and the rope winds back. If the rope doesn’t wind back, this is a sign that it needs to be replaced.

replace recoil starter - cub cadet mower

11. Damaged or Dirty Spark Plug

The spark plug might be a small part of your lawn mower but it’s definitely one of the most important. The spark plug creates the spark necessary for the engine to start and if it is damaged or dirty, then this cannot happen.

How To Fix It

You can look at the spark plug to see if it needs cleaning. If there is an obvious build up of carbon then that tells you everything you need to know.

In some cases, there may be damage or cracking to the insulator or electrodes and you can check the function of the spark plug using a spark plug tester. If no spark appears when you use the device, you will need to buy a new spark plug.

12. Dead Or Bad Battery

There is a battery in your Cub Cadet lawn mower and without this, the mower won’t start. The battery must be fully charged and there should be no loose connections or corrosion on the battery terminals.

How To Fix It

If there are clear signs of corrosion, you can clean this using a solution of water and baking soda and using a wire brush for scrubbing.

Any loose connections should be reestablished and you should ensure that the battery is sufficiently charged. Using a multimeter, make sure that the reading is above 12.7 volts. If it isn’t, you’ll need to charge the battery.

As batteries age, they lose efficiency and eventually, they’ll stop holding their charge. It is at this point that you’ll need to buy a new battery.

13. Bad Starter Solenoid

The starter solenoid on your Cub Cadet lawn mower is an electromagnetic switch which gets the starter motor going. When this isn’t working, your lawn mower won’t fire up.

A good way to tell whether there might be an issue with the starter solenoid is by listening to what happens when you turn the ignition key. If you hear a clicking or humming sound, this could suggest there is a problem. Also look out for melted components and smoking.

How To Fix It

You can use a screwdriver to bypass the solenoid by placing it over the wires and attempting to start the mower. If you can do this without any problems then there’s a good chance that the starter solenoid needs to be replaced.

14. Bad Ignition Switch

If you insert the ignition key and turn it but nothing happens then it could be that the ignition switch is the cause of your problems.

How To Fix It

Use a multimeter to test the ignition switch and if it has malfunctioned, you can replace it with a new one.

15. Damaged Fuel Cap

If you look at the fuel cap on your Cub Cadet lawn mower, you will notice that there is a small air vent. Sometimes, this can become clogged and it forms a vacuum inside the tank which stops fuel from being drawn out.

Take a look at the cap to see if there are any blockages within the vent. If there are then you can bet your bottom dollar that this is the root of the problem.

fuel cap - cub cadet mower

How To Fix It

You can also check whether the fuel cap is the problem by taking it off and trying to start the mower again. If it does start then there’s a good chance you’ve located the source of the issue.

You can try to clean the vent in the fuel cap although this is notoriously difficult. In most cases, you’ll just need to buy a new one.

Other Cub Cadet Lawn Mower Issues

The issues we have already talked about in this guide will largely fix most power problems with a Cub Cadet mower. But there are a couple of other things that you may be wondering when your Cub Cadet mower won’t start. Here are a couple of other common issues.

What Would Cause A Cub Cadet Lawn Mower Not To Turn Over?

While Cub Cadet is a reliable brand, you may experience issues with power from time to time. In some instances, the lawn mower may not turn over and this could be as a result of many issues.

Typically, you might look at the quality of the fuel as bad fuel can prevent the mower from turning over. Other problems could be a dirty carb or clogged filters so these will all need to be checked and cleaned. While you’re at it, it’s also worth checking the fuel lines for any blockages or dirt.

Cub Cadet Lawn Mower Smoking Up

If you notice that your Cub Cadet lawn mower is smoking, this can be incredibly concerning. This usually happens when there is oil in the cylinder and when it starts to burn off, it causes smoke.

There may be other issues at play here such as overheating and various parts burning up because of friction when there isn’t enough oil. Parts like the valve train, piston ring and gaskets should all be checked.

Cub Cadet Riding Mowers

Many of the things we have discussed in this guide could also relate to a Cub Cadet riding lawn mower that won’t start so it’s definitely worth checking everything out before considering the following.

Other problems that might affect your Cub Cadet riding mower may be to do with steering. Common issues that affect steering include incorrect tire pressure or worn components within the steering system. In some cases, it could be an issue with tracking, especially on a zero turn mower and in this case, you would notice that the mower has a tendency to veer in one direction or the other.

Cub Cadet Lawn Mower Troubleshooting: When To See A Professional

Being able to fix your own Cub Cadet lawn mower is always going to be the easiest and most affordable option. However, even the most DIY savvy lawn mower owners may sometimes find themselves scratching their heads and wondering why won’t my Cub Cadet lawn mower start?

If you are ever in any doubt about what is causing the problem or how to fix an issue then this isn’t something we would recommend taking on without professional help. If you try to perform maintenance on your mower when you don’t know what you’re doing, you could cause damage, void your warranty, or even injure yourself. It’s not worth it so just call a pro and let them handle the issue for you.

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Andrew Fisher

Andrew Fisher

Andrew is a dedicated father of three who really takes pride in his lawn and garden. You'll find Andrew behind the scenes of almost everything Edge Your Lawn produces. When he's not helping readers find all the information they need, he's in his backyard working on his lawn and garden landscaping. This year he hopes to build an outdoor deck and sort out his veg patches.