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 your mower starting problems. So many that it can be a little overwhelming to know exactly what to check and where to start.
Toro lawn mowers won’t start when there is a lack of fuel or air to the engine; a bad spark plug; or a failure in the electrical system. This can be caused by blockages in the fuel system, a bad gas cap, dirty carburetor, plugged air filter, bad battery and more.
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Follow all safety instructions provided in your equipment operator’s manual prior to diagnosing, repairing or operating. Consult a professional if you don’t have the skills, knowledge or are not in the condition to perform the repair safely.
Reasons Why Your Toro Mower Won’t Start
Toro 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 you Toro won’t start.
I’ve been yelled at by a customer because his new lawn mower wouldn’t start only to later find out, when I picked it up for repair, he had run out of gas. Now, this customer is a very intelligent man who became so upset he didn’t take the time to check his gas tank. Forgetting to check the gas tank can happen to anyone.
Repair: Add fresh fuel to your gas tank.
Using the Wrong Type of Gas or Old Gas in Your Toro Mower
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 of 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 Gasoline 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 be the cause the parts in your fuel system 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. Read more about the advantages of using Sea Foam Motor Treatment in your Toro.
Toro 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, 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 plugged? 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 your have a problem with your gas cap.
Repair: Try to clean your gas cap to open the vent. You will have to replace the cap if you can’t get it to vent.
Bad Spark Plug or Loose Connection on Toro Mower
A spark plug that is excessively dirty from carbon and oil buildup can foul out causing your engine to misfire. A spark plug that is not properly gapped and doesn’t make 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 cracked porcelain insulator. Replace with a new spark plug(s). Make sure they are correctly gapped.
Air Filter Plugged in a Toro Lawn Mower
Air is a required to start your lawn mower and keep it running. Because you are using your Toro in the outdoor elements with grass and dirt be 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. Read more about the effects oCleaning out your air filter and replacing it when necessary will prevent any serious problems caused by lack of air.
Repair: Remove your air filter from the air filter housing to check for dirt build up. Clean a paper air filter by tapping it against a hard surface to knock as much dirt out as you can.
Check to make sure you can still see light through the paper element by holding up to the light. You’ll have to replace your filter if you can’t see light shine through the paper.
If your Toro mower uses a foam filter, you’ll want to replace it with a new filter if it is brittle, torn or has brown spots on it. To clean your foam filter, wash it with a mild dish soap to remove as much dirt and oil as you can get out of the filter.
Rinse the filter until the soap is removed. Squeeze the water out of the filter and lay flat to air dry. Laying in the sun will help it dry faster. Once it is dry, lightly coat the filter with an oil designed for foam filters.
Toro Fuel Pump is Bad
Overtime, your Toro fuel pump may go bad. Gas sitting in the fuel pump can degrade the plastic and components of the pump so it no longer is able to hold pressure required to pump 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 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.
Plugged Fuel Filter in Toro Mower
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.
Toro Has a 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 line online or at your local hardware store.
Clogged & Dirty Carburetor on Your Toro
The carburetor on your Toro mower regulates the mixture of gas and air needed to create a 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 the carburetor 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.
Bad Battery, Loose Cables or Corroded Terminals on Your Toro Mower
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 will want a reading at 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.
Bad Toro 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.
Bad Toro 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 check 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.
Bad Starter Solenoid on Your Toro Lawn Mower
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.
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.
Faulty Charging System on Your Toro Mower
A charging system that is no longer able to keep your Toro mower running can cause it to die while you are mowing. It can also cause your battery to be drained preventing it from starting the next time you go to use your mower.
A bad stator or alternator can be the problem. I show steps on how to test your charging system here using an ohm meter.
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.
Incorrect Toro Operating Procedure
Toro implements safety precautions with their lawn mowers that require certain steps to be followed when starting and operating the lawn mower.
FIX: 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.