Technical How many brushes are grounded in a 4 brush starter motor?

Maybe @e1956v can assist?
I guessing 2, but don’t really know.

But I have one of the 4 brushes that may have had insulation on it, or not. This starter has slots in the housing to access the brushes. Then a band around the access slots, under the band is a rubber strip to keep moisture/ect out.
My rubber protector fell apart in pieces, and I can’t tell if what I saw on the brush wires was left of insulation or the rubber band around the holes.
I pulled this starter off of an engine that was in a fire, other than that one set of wires the rest of it looks like new.

Thanks

 

If it has a single power connection point, two should be grounded.

 

Thanks Steve, just ohmed it out and two opposite brush “cases” are ground to the starter.
Whew!