What must be in the "on" position for some ATVs to start?

For certain ATVs to start, the ignition switch must be in the "on" position. The ignition switch is a crucial component, as it controls the electrical systems of the ATV, including the ignition system that sparks the engine to life. If the ignition is switched off, no electrical power is supplied to the engine components, making it impossible for the ATV to start, regardless of the positions of other controls.

In comparison, while the throttle, parking brake, and fuel supply valve are important for the operation and safety of the ATV, they do not directly control the starting mechanism. The throttle is involved in controlling speed, the parking brake ensures stability when the ATV is stationary, and the fuel supply valve regulates fuel flow. However, they do not initiate the starting process as the ignition switch does.