Final answer:
Increasing the gap of the breaker points in a magneto requires a higher voltage to produce a spark, potentially affecting the system's efficiency and reliability.
Step-by-step explanation:
Increasing the gap of the breaker points in a magneto can impact the voltage needed to produce a spark across that gap. A magneto creates a spark by spinning a magnet quickly in front of a wire coil, which induces a large voltage across the gap made by the ends of the wires. If the gap is increased, the required voltage for the spark to jump across it will also be higher. Given that about 75 kV is needed for a 2.5 cm gap, a wider gap would necessitate an even stronger electric field to achieve breakdown. However, such adjustments to the gap can affect the efficiency and reliability of the ignition system. The magneto's ability to generate a sufficient voltage could be compromised, potentially failing to produce a spark or requiring the system to work harder, possibly leading to quicker wear out or failure.