How to Troubleshoot a Troy-Bilt Riding Mower

Verify that there is enough fuel in your Troy-Bilt riding mower if it will not start. Refill the gas tank if necessary. If there is old gas in the tank from last season, add a little fresh gas to the tank, crank the engine and allow the mower to run until the gas tank is empty.

Fill the tank entirely with new gas then add a dose of gas additive to make the mower run smoothly.

Attempt to turn on your Troy-Bilt riding mower. If the engine cranks but does not start and there is gas in the tank, you will need to open the front engine cover. This cover is the front hood over your engine. Run your fingers until the front lip of the cover to find the latch mechanism to pop open the hood.

Disconnect the black plug wire from the spark plug. The spark plug may need to be replaced, and this is often the most likely culprit for a non-starting Troy-Bilt riding mower that cranks. Obtain a new spark plug and connect the plug wire to it. Attempt to start the engine again.

Check the air gap of your Troy-Bilt riding mower. The air gap should be between 0.010- and 0.015-inch in width between the magnetic coil and the flywheel parts at the back of the engine assembly. Locate the magnetic coil by following the spark plug wire back to it. The flywheel is directly behind the coil in a Troy-Bilt riding mower. Measure the air gap between the two and ensure it falls within the 0.010- and 0.015-inch specification.

Use a wrench to loosen your Troy-Bilt riding mower's magnetic coil. Press on the outside of the coil to close the gap incrementally, as necessary, to adjust the width of the gap. Remeasure it.

Replace your Troy-Bilt riding mower's engine cover and crank the engine. It should start and run effectively.