Wiring diagram I'm looking at right now for a Bristol compressor shows start and run caps in series with start winding. The relay is to make/break circuit to start cap. Start cap is wired in parallel with run cap but one leg is make/break inside relay.
2s1r5c on pot. relay or 5,2,1 common, start, run. 1 & 2 are make/break for start cap.