With so many things that can prevent your Troy-Bilt from starting, it’s hard to know even where to begin looking for the problem. I have put together a list of all of the items you should check when looking for your starting problem on a push mower, riding mower, lawn tractor, or zero turn.
A Troy-Bilt mower won’t start when there is a fuel restriction due to clogged filters and fuel lines, a dirty carburetor, a bad gas cap, a bad battery, a faulty spark plug, a bad switch, a bad ignition switch, or starter solenoid.
Keep reading for additional items that cause a starting problem. Remove the spark plug wires before you begin making any repairs.
Additional guides that may help with your starting problem:
- Troy-Bilt mower clicks but won’t turn over or crank
- How to tell your Troy-Bilt solenoid is bad
- Why does my Troy-Bilt battery keep dying
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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 Troy-Bilt Mower Starting Problem: Fuel, Air, and Spark
An internal combustion engine on a Troy-Bilt mower requires fuel and air to be introduced to the cylinder. This mixture is compressed and ignited with spark to form combustion.
Before beginning to check for starting problems verify these 4 things:
- The fuel shut-off valve is open allowing fuel to flow out of the fuel tank.
- There is sufficient fresh fuel in the fuel tank.
- The parking brake is engaged or the bail lever is engaged.
- The PTO switch is off (riding mower, lawn tractor, and zero turn).
- The choke is in the closed / on position to start a cold engine.
Check for a Fuel Problem
Old gas is often the root cause for fuel-related issues resulting in components not functioning or clogs developing.
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.
- If the mower attempts to start or starts, then you have a problem with the fuel system.
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 Troy-Bilt 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.
- Manual-choke model
- 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 Troy-Bilt 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 Why Your Troy-Bilt Mower Won’t Start
1. Gas Tank is Empty
Needing gas to make a gas-operated Troy-Bilt lawn mower run is pretty much a given. I only mention it here because, when you’re frustrated with your starting issue, you can easily forget about the most obvious items preventing your mower from running.
FIX: Add fresh fuel to an empty gas tank
2. Wrong Type of Gas or Old Gas
Right Gas for a Troy-Bilt Lawn Mower
Using the wrong kind of gas in your lawn mower can cause more damage to your lawn mower than not starting. There are so many types of gas on the market today and it can be difficult to know which type to use.
A Troy-Bilt 4-cycle engine requires regular unleaded gasoline. It’s important to select gasoline that has no higher than a 10% ethanol content and it must have a minimum of an 87-octane rating.
For small engines, like the one used in your Troy-Bilt mower, it’s always best to use gasoline with the least amount of ethanol or no ethanol. You can ensure you are grabbing the right kind of fuel by reading the label on the gas tank.
Read my article on the gas for your Troy-Bilt mower to get a more in-depth look at fuel options and the effects of ethanol.
Use Fresh Gasoline in a Troy-Bilt Mower
Running gasoline that has been sitting around for a while can cause clogging and run ability problems in your lawn mower. Gas stays at its best for about 30 days before it begins to break down and become less efficient.
This, in addition to the fact that ethanol collects moisture in the fuel system, can cause starting problems in your Troy-Bilt lawn mower.
Ethanol can cause corrosion and degradation of parts in your fuel system and engine. The gummy substance left behind by old fuel can clog your fuel system causing your Troy-Bilt not to start.
FIX: 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 Troy-Bilt.
3. Bad Spark Plug or Loose Connection
Your spark plug(s) can fail when the tip is excessively dirty from carbon buildup. A spark plug that is not properly gapped and doesn’t make a good connection can also contribute to your engine misfiring and starting problems in your Troy-Bilt.
FIX: 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 and the spark plug wires are secure.
4. Clogged Air Filter
It is essential to have air for your Troy-Bilt mower to start. Your mower uses an air filter to keep outdoor elements like dirt and grass clippings from entering the engine.
When your filter becomes plugged, your engine will work harder, overheat and shut down.
Checking, cleaning, and replacing your air filter is one small item you must take care of to help keep your engine in operating at its best. The cost of an air filter is pretty minor in relation to the cost of significant internal engine damage that can be caused by overheating the engine.
FIX: Remove your paper air filter from the air filter housing to check for dirt buildup. 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 it up to the light. You’ll have to replace your filter if you can’t see light shine through the paper or you find the filter is damaged or covered in oil.
If your Troy-Bilt 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 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 a clean engine oil.
5. Fuel Pump is Bad
Over time, your Troy-Bilt fuel pump may go bad. It will no longer be able to hold the pressure that is required to pump gas to the carburetor.
Old gas sitting in the fuel pump can degrade the plastic and components of the pump over time. It may begin leaking at the seams or damage the internal components.
If your fuel pump is leaking, you must replace it. If you are unable to see the damage, you will need to test your pump to check if it is still operating properly.
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 line 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.
FIX: Replace your fuel pump if you are not receiving a constant or pulsating flow out of the pump.
6. Plugged Fuel Filter
I replace my fuel filter at least once a year to make sure I’m running a good filter. I know the bigger problems that can happen when my fuel filter doesn’t filter correctly.
Note: Most push mowers don’t use a fuel filter so don’t worry if you can’t find one on your push mower.
The function of a fuel filter is to filter out dirt and other debris that may have gotten into the fuel tank. A filter can become clogged with dirt or gummed up by old fuel.
FIX: A clogged fuel filter must be replaced with a new one.
7. Blockage in the Fuel Line
If you haven’t realized a common theme yet, you will. Bad or old fuel can cause clogging throughout your fuel system. This includes the fuel lines as well.
You are not able to visibly see a clog in your fuel lines so you’ll have to check one section of the hose at a time. Do this by starting and stopping fuel flow using the fuel shut-off valve located under your fuel tank.
If you don’t have a shut-off valve, just use a clamp on your fuel line to start and stop the flow. You will want to check each section of the hose to check for clogging.
I like to start with the hose furthest away from my fuel tank and then work my way toward the fuel tank. This way, if I know I have fuel flow further away from the fuel tank, then I don’t have to check the sections of the hose closer to the tank. It saves a little time.
FIX: Once you find a clogged line, you need to try to remove the blockage. Do this by removing the line from your Troy-Bilt.
Spray carburetor cleaner into the tube to loosen the blockage. Then use compressed air to blow air into the line and remove the clog.
If you are unable to dislodge the clog, you will need to replace your fuel line. You can purchase a mower fuel line at your local hardware store or online.
I do recommend replacing your fuel lines if the lines are dry or cracked even if you don’t find a clog in them.
8. Clogged & Dirty Carburetor
The carburetor on your Troy-Bilt mower regulates the mixture of gas and air needed to create combustion in the engine’s cylinder.
When your carburetor is gummed with dirt and old fuel, it can prevent your engine from getting the gas and air mixture it needs to start and run. Your carburetor will need to be cleaned and any failed components must be replaced.
FIX: If you are a little mechanical you should be able to handle cleaning your carburetor. Your carburetor includes a lot of small parts.
If you are unsure about cleaning your own carburetor, you can have your local small engine mechanic clean your carburetor or you can replace it with a new carburetor.
Clean the carburetor by taking it apart and using carburetor cleaner to clean the carb 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.
9. Loose or Corroded Cables, Wiring, or Terminals
Your Troy-Bilt will not start with loose or corroded cables, wiring, or terminals. Check the electrical connections and make sure they are securely attached and free of corrosion.
FIX: 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.
10. Weak or Bad Battery
A weak battery won’t provide the power needed to power the starter and turn over the engine. Test the 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 Troy-Bilt battery does not hold a charge, you will need to replace it with a new battery.
11. Bad Safety Switch
Your Troy-Bilt 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.
12. Bad Ignition Switch
You insert the key into your ignition switch and turn it only to find your Troy-Bilt doesn’t start or even turn over. The ignition switch could be the problem.
FIX: You can use a multimeter to test the ignition switch. Replace the switch if bad.
13. Bad Starter Solenoid
A Troy-Bilt 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 Troy-Bilt mower solenoid may be bad is when a wire attached to your solenoid gets hot and begins to smoke or melt.
FIX: Test your Troy-Bilt mower solenoid by following the steps here. Replace your solenoid if it is found to be bad.
14. Bad Starter Motor
Once you have ruled out the battery, cables, wiring, ground, and starter solenoid as being the reason your Troy-Bilt won’t turn over, it’s time to look at the starter. The starter can be removed and tested.
I recommend having your local repair shop that specializes in starter and alternator repairs test your starter and rebuild it if possible before just throwing a pricey new starter at your Troy-Bilt mower.
15. Bad Recoil on a Push Mower (Manual Start)
Some Troy-Bilt push mowers use a recoil with a rope to start the mower. A recoil is known to wear out over time.
You may have pulled the rope and it no longer retracts. Sometimes, the rope can be restrung on your recoil and other times parts, including a pulley, spring, or clips, may have failed.
FIX: You can attempt to replace the spring and restring your Troy-Bilt 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. Blown Fuse
A fuse is installed to protect your Troy-Bilt’s electrical system. Check your mower to make sure you don’t have a blown fuse.
FIX: Replace your blown fuse with a fuse with the same amperage as the fuse you are replacing. If you continue to blow fuses, you should bring your mower to your local Troy-Bilt dealer or lawn mower repair shop to troubleshoot the root cause.
17. Faulty Charging System
The charging system will not be the main culprit to a mower not starting, but it can be the underlying problem. The bad charging system can 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 also be a problem. I show steps on how to test your charging system here using an ohmmeter.
FIX: Have your local Troy-Bilt dealership or lawn mower small engine repair shop 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 you purchased doesn’t resolve your starting problem.
18. Gas Cap Won’t Vent
The gas cap on your Troy-Bilt mower is designed to vent and allow air to pass through the cap. When the vent is clogged, your fuel tank will act like a vacuum and not allow any gasoline to flow out of your gas tank.
When this happens, your engine is not getting any fuel and therefore will not start.
To check whether your gas cap is venting, remove the cap to see if your lawn mower will start and run. If it does, place the cap back on the fuel tank and allow it to continue to run.
You are checking to see if your mower eventually begins to sputter and shut down because your fuel supply is being restricted. If this happens, there’s a good chance your gas cap is bad.
FIX: Clean your gas cap to try to clear the clog. Replace your gas cap with a new cap if you are unable to get your cap to vent correctly.
19. Incorrect Starting and Operating Procedure
Troy-Bilt implements safety precautions with their lawn mowers that require certain steps to be followed when starting and operating the lawn mower.
This includes not having the choke on to restrict airflow needed to start a cold engine.
FIX: Refer to your Troy-Bilt 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.
Starting Problems FAQ
A Troy Bilt lawn mower won’t start when fuel is restricted due to a dirty carburetor, clogged fuel filter, or old gas. An air restriction and lack of spark can cause a starting problem due to a clogged fuel filter, stuck choke, fouled spark plug, or bad ignition coil.
First check the fuel supply and maintenance parts including the air filter, spark plug, fuel filter, and old gas when your lawn mower won’t start.
When the mower engine turns over and cranks but won’t start check for a dirty carburetor, clogged air filter, fouled spark plug, and clogged fuel line.
Still Experiencing Troy-Bilt Lawn Mower Problems?
Own a lawn mower long enough, you’ll start running into problems with it starting, not continuing to run, smoking, leaking gas, giving a bad cut, vibrating, or another issue.
To help you save time and money, I have put together a guide to help you troubleshoot the next problem that develops on your Troy-Bilt mower.
You can find this guide at Common Troy-Bilt Lawn Mower Problems & Solutions.
If you are unsure how to perform diagnostics and repairs on your lawn mower safely, it’s best to have a professional complete the repairs.
This will help you avoid personal injury or additional damage to the mower. Your local Troy-Bilt lawn mower dealership or lawn mower repair shop will be able to help you solve your problem.