If I recall correctly, the original box on my generator had the two relays inside it. As Bloo said, one out be the cutout and the other a voltage regulator. If I order this unit
https://www.steinertractor.com/ABC074-6-Volt-Voltage-Regulator
i am guessing this would work with my third brush generator. However I'm still unsure as to where the two wire emerging from the generator would be run. One is insulated, the other is thinner and uninsulated.