It is highly unlikely that an armature air gap set too wide will prevent an engine from starting and running.

When assessing whether a wider armature air gap can affect an engine's ability to start and run, it is important to understand the function of the armature and its air gap in relation to an engine’s ignition system. The air gap in the ignition system, particularly in relation to the armature in a two-stroke engine or a magneto ignition system, is critical for producing a sufficient magnetic field. However, if this gap is set too wide, while it may reduce efficiency and affect performance somewhat, it is not necessarily a complete barrier to starting or running the engine.

An air gap that is excessively wide can lead to weaker magnetic coupling, which may result in a lower output from the ignition system. However, many engines can still generate enough voltage to initiate combustion despite this inefficiency. Therefore, it is not highly likely that an oversized air gap would outright prevent the engine from starting or running; it would more likely result in suboptimal performance rather than failure to operate.

In this context, the assertion that it is highly unlikely for a wide armature air gap to prevent engine operation holds true, underscoring the concept of robustness within engine design and operational tolerances.