Magneto /Ignition Switch connection clarification

[jliltd]

Originally Posted by azrv6

Wiring diagram Z-26 of Bob Nuckolls Aeroelectric Connection has a detailed diagram for wiring the Gerdes A-501-2 switch including wire gauge and how to handle the grounding and the shields. You can download a pdf of the book for free.

Here is a screen grab of the diagram:

Attachment 18720

I do have one question about the above diagram. The schematic makes perfect sense for a non-impulse right magneto. But then the switch contact terminal matrix table at the bottom of the page seems to indicated grounding the left magneto during start, rather than the right. That is if "BO" terminal presumes ground. Which might be wrong as I am unclear as to what BO means. Any idea what the BO terminal used for if anything?

[JosephineJ79]

BO equals Body Odor.