[JEFryar]

MT,
The stop lever or an equivalent system cuts fuel flow to the engine to stop it. This may be a manual lever, a solenoid which opens only with the ignition key on or a pushbutton which pulls the solenoid in to stop the engine. In each case you will need to make sure that whichever system is on your engine it is in the "run" position and allowing fuel to flow to the injectors.
JEF