Which statement best describes the function of impulse coupling in a magneto system?

• A. It prevents the magneto from delivering a spark at low RPM.
• B. It is used to switch the magneto off during certain engine operations.
• C. It snaps to deliver a spark to the cylinder at the correct timing when released, enabling ignition.
• D. It reduces engine vibration.

Answer: (C)

Impulse coupling stores energy as the magneto rotor spins during cranking and then releases it in a quick snap. That release advances the rotor’s position enough so the spark occurs at the proper time as the piston nears top dead center, giving a strong, reliable ignition at low engine speeds. As the engine speeds up, the mechanism disengages and the magneto returns to its normal timing. This is not about turning the magneto off, reducing vibration, or simply blocking sparks at low RPM.