My Riding Mower Is Getting Fuel and the Spark Plug Is Fine but It Will Not Start

Safety Settings

• It’s common for riding mowers and lawn tractors to have safety settings that prevent starting up, even if the spark plug is working and you have enough fuel. For example, the John Deere L1742 lawn tractor has a button that must be engaged to make sure that the blade has not been lowered. Your throttle may also need to be in a neutral or start position before you turn the key or press the ignition switch. Other mowers have a safety switch under the driver's seat so that the mower can’t be started unless someone is sitting in the seat.

Fuel System

• You might have fuel in the gas tank, but it may not be enough. Fuel must get past the primer and into the carburetor before the engine will start. If you have less than a third of a tank, check how your riding mower is sitting on your lawn. If it’s on a slope or an incline, chances are that the fuel is sitting in the back of the tank. There’s also a chance that the fuel filter or gas line is clogged. Inspect those for any obstructions or debris.

Choke

• A choke system allows you to control how much fuel gets to the carburetor to create an ignition vapor. An open choke makes the fuel mixture richer. It’s possible that if your riding mower has a choke control that’s always on, you are flooding the carburetor with fuel. This prevents a spark to start the engine. Check to see if your choke control is on or that the choke system is not damaged and set to an open position.

Oil

• Oil is the lifeblood of the engine, constantly lubricating the moving parts during operation and keeping them cool. If you don’t have enough oil in your engine, those parts can seize and cause severe damage since there’s nothing to buffer the hot metal from grinding on itself. An oil sensor to detect oil levels could prevent a start that would cause this damage. It’s always a good idea to check the oil prior to your first start and change it according to your mower’s specific maintenance plan.