17 Reasons Your Toro Lawn Mower Won’t Start (Solved!)

Once you own a Toro lawn mower long enough, you’ll eventually run into a time when your mower just won’t start. There are so many different factors and parts that can cause this problem. So many that it can be a little overwhelming to know exactly what to check and where to start.

A Toro lawn mower won’t start when there is a lack of fuel, air, and spark.

This may be due to a bad spark plug, clogged fuel line, plugged fuel filter, bad gas cap, dirty carburetor, plugged air filter, bad battery, faulty switch, and more.

Keep reading for additional reasons for your Toro starting problem. Take caution and remove the spark plug wires prior to performing repairs. Check out this article if you’re looking for starting problems specific to Toro push mowers.

More articles that may help you with your starting problem:

• How to tell your starter solenoid is bad
• Reasons a Toro zero turn won’t start
• Why your Toro mower won’t crank or turn over

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.

Troubleshoot a Toro Lawn Mower Starting Problem: Fuel, Air, and Spark

An internal combustion engine on a Toro mower requires fuel and air to be introduced to the cylinder. This mixture is compressed and ignited with spark to form combustion.

Check for a Fuel Problem

Old gas is often the root cause for fuel components to stop functioning or for clogs to develop.

Before checking for a fuel problem, if your mower has a fuel shut-off valve, make sure it is in the open position. This valve is often moved to the closed position when the mower is stored or for transportation.

Perform this test to narrow down your problem to the fuel system:

• Detach the air filter cover and remove the air filter.
• Spray carburetor cleaner into the air intake. Find out why I use carburetor cleaner and not starter fluid.
• Attempt to start your mower using the manual recoil starter or turning the ignition key (depending on your mower type)
  • If the mower attempts to start or starts, then you have a problem with the fuel system.
    • The most common fuel issues are a dirty carburetor, clogged fuel filter, and clogged fuel lines. The fuel pump may also be an issue if your mower uses one.
  • If the mower doesn’t attempt to start, you most likely have a spark plug problem.

Check for an Airflow Problem

Air is an important component needed for your engine to start. The engine must run rich to start a cold engine. This condition allows more fuel and less air into the cylinder.

Airflow is controlled by the choke. You will find a choke lever that opens the choke plate to introduce more air and close the choke plate to restrict air.

On newer Toro push mowers, you will find an automatic choke controlled by a thermostat.

Perform this test to narrow down your problem to the air supply system:

• Detach the air filter cover and remove the air filter.
• Inspect the air filter’s condition. A clogged air filter will restrict airflow. Clean the filter or replace it if it is very dirty or damaged.
• With the air filter removed, inspect the choke plate.
  • Manual-choke model
    • Move the choke lever to the on position: The choke plate should be closed.
    • Move the choke lever to the off position (on some models, this is placing the throttle in the fast throttle position): The choke plate should be open.
  • Auto-choke model
    • The choke plate should be closed when the engine is cold and moved to the open position when the engine warms.
• If the choke isn’t opening and closing correction, check the choke linkage and choke cable. Loosen a stuck choke by lubricating the linkages and choke shaft using carburetor cleaner. Replace a bad choke cable (if used on your Toro model).

Check for a Spark Problem

Spark must be released at the right time for combustion. A spark plug may fail to spark if it is dirty or damaged. It may also fail due to a loose spark plug wire, a bad ignition coil (armature), or other ignition system problems.

Perform this test to narrow down your spark problem:

• Remove the spark plug wire (boot) from the spark plug.
• Attach a spark plug tester to the spark plug ignition wire.
• With the spark plug still installed, attach the other end of the spark plug tester to the spark plug.
• Attempt to start the engine using the pull cord or electric start.
• You will see a glow in the transparent section of the tester if it is generating a spark.
• If you don’t see a glow, the spark plug may be bad or you may have a bad ignition coil. On electric start models, you may have a problem with the ignition system including the battery, wiring, and starter solenoid.

Reasons Your Toro Lawn Mower Won’t Start: 17 Starting Problems

1. Gas Tank is Empty

You know your gas lawn mower won’t run if you don’t have gas. I only mention it because, when you’re frustrated and not in the right frame of mind, you may forget this obvious reason why Toro won’t start.

You may have developed a fuel leak, the fuel gauge may be faulty, or you may have simply run out of gas.

Repair: Add fresh gas to your gas tank.

2. Choke is Not in the Right Position / Incorrect Starting Procedure

Toro implements safety precautions with their lawn mowers that require certain steps to be followed when starting and operating the lawn mower.

This includes following steps to engage the safety switches and placing the choke in the right position to start and keep the engine running.

The choke is used to restrict airflow so the fuel and air mixture runs rich to start a cold engine. Once the engine warms, the choke must be adjusted to the off position to keep the engine running.

Follow these starting procedures for most common Toro mowers:

• Toro push mowers
  • With choke lever: Place the choke to the full choke position to start a cold engine. Squeeze the bail lever against the handle and pull the starter rope to start the cold engine. Once the engine warms, adjust to the closed position to keep the mower running.
  • With auto choke: Squeeze the bail lever against the handle and pull the starter rope.
• Toro riding mowers or zero-turn mowers
  • Sit on your seat. Ensure the PTO switch is off and the parking brake is on. Make sure the mower is in the neutral position. Place the choke lever in the full choke position (closed) to start a cold engine. Turn the ignition key to start the mower. Adjust the choke lever to the open position once the engine warms.

Repair: Refer to your Toro operating manual to ensure you are operating your lawn mower correctly, so you don’t set off the safety features that shut off your lawn mower or won’t allow it to start. Each model may have slightly different starting procedures.

3. Bad Gas or Old Gas

Right Gas for a Toro Lawn Mower

Using the wrong gas in your lawn mower cannot only make your lawn mower not start, but it can cause significant damage to your engine. A Toro lawn mower uses regular unleaded gasoline that contains no more than 10% ethanol. The less ethanol in the gas, the better.

In addition to watching out for the correct ethanol content level, you must make sure your gasoline has an octane rating of 87 or greater. 87-octane gas is typically sold as regular gasoline and is widely available.

Check the label on your fuel pump for the octane level and ethanol content.

For more information on selecting the right kind of gas for your Toro lawn mower and ethanol-free options, read my article, “This is the Kind of Gas to Use in Your Toro Mower“.

Use Fresh Gas in a Toro Mower

Old gasoline can cause clogging problems in your fuel system that can prevent your engine from getting the fuel it needs to start. Gas only lasts for about 30 days before it begins to break down.

The ethanol in the fuel collects moisture. When this moisture evaporates it leaves behind a gummy substance that can clog components of your fuel system. Ethanol can also cause the parts in your fuel system to begin to degrade.

Repair: Drain and flush the fuel tank. Add fresh fuel that includes a fuel additive to stabilize and clean your fuel system like Sea Foam or STA-BIL. Read more about the advantages of using Sea Foam Motor Treatment in your Toro.

4. Gas Cap Won’t Vent

You probably didn’t notice there is a small hole in the gas cap to let air pass through so the fuel tank can vent.  When your Toro cap’s vent is clogged, the air is unable to pass through the cap and a vacuum is formed in the fuel tank.

This vacuum restricts fuel from flowing out of the tank. Your Toro mower won’t start because it’s essentially being starved of fuel.

So, how do you know your gas cap is clogged? A good indication you have a plugged vent is to remove your gas cap from the tank, start your mower and let it run. (Make sure debris doesn’t get into the tank).

Now that it’s running, replace the fuel cap and let it continue to run. If it sputters out or shuts off, it is likely you have a problem with your gas cap.

Repair: I recommend replacing the cap with a new one. You can attempt to try to clean it, but if that doesn’t work you will need to replace it.

5. Bad Spark Plug or Loose Connection

An excessively dirty spark plug from carbon and oil buildup can fail and cause your engine to misfire.  A spark plug that is not properly gapped and doesn’t make a good connection can also contribute to the starting problems with your Toro.

Repair: Remove your spark plug and inspect it for signs of carbon buildup or a cracked porcelain insulator. Replace with a new spark plug(s). Make sure they are correctly gapped.

6. Clogged Air Filter

Air is required to start your lawn mower and keep it running. Because you are using your Toro in the outdoor elements with grass and dirt tossed in the air while mowing, your air filter can become plugged.

It’s important to frequently check and clean your air filters to prevent starting and engine problems. When your Toro’s air filter is so plugged the engine can’t access air, it can overheat.

Overheating of the engine can cause internal engine damage. Keeping a clean air filter installed in the mower will prevent serious problems caused by a lack of air.

Repair: Remove your air filter from the air filter housing to check for dirt buildup. Clean a paper air filter using one of the methods below for your type of Toro filter.

Clean a Toro PAPER air filter:

• Remove the air filter cover.
• Remove the air filter.
• Remove loose dirt in the air filter housing and from the air filter cover using a clean dry cloth. Be careful and don’t allow dirt to fall into the air intake.
• Tap the air filter element against a solid surface to loosen dirt so it falls out of the filter.
• Hold the filter up to a light source. If you can see good light through the paper, go ahead and continue to use the filter. If you can’t see good light or the filter is damaged, the filter needs to be replaced with a new one.
• Install the new or clean air filter.
• Reattach the air filter cover.

Clean a Toro FOAM air filter:

• Remove the air filter cover.
• Remove the air filter.
• Remove loose dirt in the air filter housing and from the air filter cover using a clean dry cloth. Be careful and don’t allow dirt to fall into the air intake.
• Inspect the air filter for damage. If it is very dark in color, brittle, or has tears in it, it’s time to replace it with a new one. If it is in good condition, continue cleaning the filter.
• Wash the foam filter in water and mild detergent to remove oil and dirt.
• Rinse the filter until it runs clear. Squeeze the filter to remove water. Don’t wring the filter as this can tear it.
• Allow the filter to dry.
• Apply clean engine oil to the filter so it is completely covered. Squeeze excess oil from the filter. (NEVER APPLY OIL to a foam pre-filter. A pre-filter is a filter that wraps around a paper filter element. This can damage the paper filter).
• Install the filter.
• Reattach the air filter cover.

7. Fuel Pump Problem

Over time, your Toro fuel pump may go bad. Gas sitting in the fuel pump can degrade the plastic components of the pump so it no longer holds pressure to move gas.

You may be able to recognize a bad pump from gas leaking at the seams. Most of the time it’s hard to visually tell if your pump is bad so you’ll have to test it.

Verify you have a flow to the fuel pump by using the shut-off valve or clamps to start and stop fuel flow. Check for fuel flow from the fuel hose that attaches to the inlet port of the fuel pump.

Once you have verified you are getting flow to the pump, you need to check to make sure fuel is being pumped out of the pump.

Do this by disconnecting the fuel hose from the carburetor and placing it in a container. Start your mower and watch the hose for a constant or pulsating fuel flow.

Repair: Replace your fuel pump if you are not receiving a constant or pulsating flow out of the pump.

8. Clogged Fuel Filter

The fuel filter can become plugged with dirt and buildup from old fuel. This will block fuel flow. Check your fuel filter to make sure it is allowing the flow of fuel to pass through the filter into the fuel hose.

Repair: A clogged fuel filter must be replaced with a new one.

9. Blockage in the Fuel Line  

The same substances that can clog your fuel filter can also clog your fuel lines. You’ll want to check sections of your fuel hose for blockages by removing the end of a hose and placing it in a container.

Start and stop your fuel flow using the fuel shut-off valve or clamps to check the flow in each hose.

Repair: To clear a clogged line, remove the fuel line, spray carb cleaner into the tube, and use compressed air to blow air through the tube until the line is free of debris and gummy residue.

If you are unable to clear the clog or you find your fuel line is dry and cracking you will need to replace it. You can find fuel lines online or at your local hardware store.

10. Clogged & Dirty Carburetor

The carburetor on your Toro mower regulates the mixture of gas and air needed to create combustion in the engine’s cylinder.

When the carburetor is no longer able to do its function because blockages have formed in the carburetor, your Toro may not start. The carburetor must be cleaned and any failing components replaced.

Repair: If you are a little mechanical you should be able to handle cleaning your carburetor. Clean the carburetor by taking it apart and using carb cleaner to clean it, including the float bowl and needle.

You can find steps for cleaning your carburetor here. If your carburetor is too dirty to clean adequately, you should replace it.

11. Bad Battery, Loose Cables, or Corroded Terminals

Your Toro will not start with a bad battery, loose cables, or corroded terminals. Confirm your battery terminals are not corroded and are attached securely to the battery.

Repair: Clean corroded terminals in a baking soda solution containing 2 cups of water and 3 rounded tablespoons of baking soda. Use a wire brush to scrub the terminals clean.

Test your battery with a multimeter. You need a reading of about 12.7 volts. Place on a charger to charge your battery if your reading is less than this.

Read more about the steps and items needed to charge your battery here. If your battery does not hold a charge, you will need to replace it with a new battery. 

12. Bad Safety Switch  

Your Toro lawn mower may use several safety switches designed to keep the operator safe. The manufacturer installs safety switches to prevent the mower deck to run without the operator present.

It also has a safety switch involved to not start when your parking break isn’t engaged. If these safety switches fail, your mower may not start.

FIX: Test the switch using a multimeter or you can temporarily bypass the safety switch to identify a bad switch. Do not operate a mower without the safety switch. 

Never run a mower when a safety switch is bypassed. You never know when you will encounter a situation where the safety switch can save you from serious injury.

13. Bad Ignition Switch or Ignition Coil 

You insert the key into your ignition switch and turn it only to find your Toro doesn’t start or even turn over. The ignition switch or ignition coil could be the problem.

Repair: You can use a multimeter to test the ignition switch. Replace the switch if bad. After you have checked your spark plug is working, check the continuity of your ignition coil using a multimeter. Replace the ignition coil if you find a break in the continuity.  

14. Bad Starter Solenoid

A Toro mower solenoid is an electromagnetic switch that is like an on-off switch that actuates the starter motor to turn over the engine. A click or hum when turning your ignition key is an indication to check your solenoid.

Another indication your Toro mower solenoid may be bad is when a wire attached to your solenoid gets hot and begins to smoke or melt.

Repair: Test your Toro mower solenoid by following the steps here. Replace your solenoid if it is found to be bad.

15. Bad Recoil on a Toro Push Mower 

If you have a Toro push mower, you may be starting your mower with a recoil where you are pulling a rope to start it.

A recoil can fail due to a bad pulley, a loose or missing spring, or broken clips preventing you from being able to start your mower with the pull of the string.

Repair: You can attempt to replace the spring and restring the recoil. If it does not work because other components in your recoil are damaged such as the clips or the pulley, you are better off just replacing the recoil assembly.

16. Low Compression

17. Faulty Charging System 

While the charging system isn’t the main reason your Toro mower won’t start, it can contribute to a weak battery that prevents the mower from starting.

When the charging system fails to charge the battery, the battery may not be able to start the mower the next time you go to use it.

A bad stator or alternator can be the problem along with several other electrical parts. Read this article to test your charging system here using an ohmmeter. 

FIX: Have your local Toro dealership check your charging system to isolate the problem. If you don’t have experience with charging systems, you will most likely just be replacing electrical items until you find one that works.

This can get very expensive because most parts stores won’t let you return electrical parts if you find a part your purchased doesn’t resolve your starting problem.

Frequently Asked Questions

Still Having Problems with Your Toro Lawn Mower?

It would be great to own a problem-free lawn mower, but it’s never the case. No matter what brand mower you own, you’re going to run into problems the longer you own it.

To help you troubleshoot your mower problems, I have put together a list of common problems along with causes and solutions to fix them. Check out Common Toro Lawn Mower Problems and Solutions to learn more.