Troubleshooting Tips If a Riding Mower Won't Start



If your riding mower won't start, start with the obvious–is there gasoline in the tank? Sounds silly, but it happens. Make sure there's enough gas in the tank, and that it's fresh. Over time, gasoline loses its volatility–or ability to vaporize and burn. Oxidation can also occur, leading to a buildup of varnish and gum that will clog the fuel lines and carburetor. If the gas is older than 30 days, drain the gas tank completely and add fresh gas.

View this troubleshooting video for more tips on starting your mower when the engine spins but won’t start.


Dead Battery

If the riding mower makes no sound when trying to start it, the battery might be dead. Even if you've recently charged the battery in your riding mower, it may no longer be able to hold the charge. Replace the battery if it's dead or no longer holds a charge. Check out this video for additional troubleshooting tips when your riding mower if it makes no sound when you turn the key.


Bad Ignition Switch

Another problem may be the ignition switch. The ignition switch supplies power to the electrical components of the engine. If the engine in your riding mower won’t stop when the key is turned to off, or the engine won’t start when the key is turned to on, the most likely problem is the ignition switch.

You can easily check the ignition switch by removing it from the mower and using a multimeter to check for continuity between the S and B terminals. If the switch is bad, follow the instructions in our repair guide How to Replace an Ignition Switch in a Riding Lawn Mower.


Failed Starter Solenoid

It’s easy to blame the starter solenoid when your mower won’t start when you hear a click but the engine doesn’t spin. Before you buy a new solenoid, perform the troubleshooting in the video Riding Lawn Mower Engine Clicks But Doesn't Turn Over If the solenoid failed, replace it using the steps in our repair guide How to Replace the Starter Solenoid on a Riding Lawn Mower.


Dirty Spark Plug

A dirty spark plug won't be able to produce a spark or may misfire, causing the riding mower to not start or it may be difficult to start. Try cleaning the spark plug to see if that helps; if not, follow the instructions in our repair guide How to Replace the Spark Plug in a Riding Lawn Mower.


Bad Ignition Coil

The ignition coil produces the energy needed to create the spark for the spark plug. If the ignition coil is bad, the riding mower may stop after running for a while and not start again until it has cooled off. You can check the coil by removing the kill wire from the coil and checking for a spark. If you know the spark plug is good but you have no spark, replace the ignition coil following the instructions in our repair guide How to Replace an Ignition Coil on a Riding Lawn Mower.


Clogged Fuel Filter

If the spark plug needs replacing, it might be a good time for a complete tune-up. When doing a tune-up, you also should replace the fuel filter. A dirty or clogged fuel filter won't protect the carburetor from debris and will result in poor performance and difficulty starting the riding mower. Our repair guide How to Replace a Fuel Filter on a Riding Lawn Mower can help get you going again.


Carburetor Problems

A clogged carburetor or worn carburetor seal prevents the air and fuel mix from reaching the engine cylinder, which keeps the riding mower from starting or causes the engine to die shortly after it starts. Sometimes, cleaning the carburetor will get it running again. If not, you can rebuild the carburetor. Learn how to do both in our repair guide How to Rebuild the Carburetor in a Riding Lawn Mower.

If you're pressed for time or simply want an easier fix, you can replace the complete carburetor. See how easy it is in our repair guide How to Replace a Carburetor in a Riding Lawn Mower.

Check out our DIY Riding Mower and Tractor Repair section for more troubleshooting tips and repair instructions.