1. Idle start switch. Normally Open, closed only at idle. Prevents engine start except at idle. Should have extended spring arm to permit overtravel passed 'idle' without damage to switch.
2. Start Switch. Normally Open, closed when 'start' command given by starter servo.
3. Kill Switch. Normally Open, closed on 'kill' command from starter servo.
4. Throttle Kill Switch. Normally Open, closed by low throttle trim.

NOTE: Switches 'C' and 'D' are not both necessary as they accomplish the same purpose. Switch 'D' would be used by itself on a no starter installation.

Micro switches from a wide variety of types are available from electronic supply houses and from Radio Shack.