A technician troubleshooting a magneto finds severe arcing and pitting at the breaker points, along with a weak spark at the plugs. Which component, when defective, is most likely responsible for this condition?
- AThe distributor gear
- BThe impulse coupling spring
- CThe primary coil retard breaker
- DThe condenser (capacitor) connected across the breaker points
Show answer & explanationAnswer & explanation
Correct answer: D. The condenser (capacitor) connected across the breaker points
The condenser is wired in parallel with the breaker points to absorb the self-induced voltage surge as the points open, minimizing arcing and allowing rapid collapse of the primary field for a strong secondary spark. A weak condenser lets excessive arcing occur at the points and reduces spark intensity. The impulse coupling and distributor gear are mechanical timing components unrelated to point arcing, and there is no 'retard breaker' component.
Why the other options are wrong
- A. The distributor gear routes high voltage to the correct cylinder, unrelated to arcing.
- B. The impulse coupling only affects cranking speed spark advance, not point arcing.
- C. This is not a real magneto component.
Magneto Condenser (Capacitor)
A capacitor wired across the breaker points that absorbs induced voltage to prevent arcing and ensures rapid primary current collapse for a strong secondary spark.
- Wired in parallel with breaker points
- Prevents point burning/arcing
- Enables rapid magnetic field collapse
- Weak condenser causes weak spark and pitted points
Memory trick: Condenser catches the spark that would burn the points