How to wire voltage regulator on a 610B

I bought a 610B with a VH4D Wisconsin engine. The regulator has 4 terminals labeled F-2-3-4. Only the F and 3 have wires connected to them. Can anyone tell me what should be hooked to the other 2 terminals?

You didn't say which charging system you had(flywheel or external alternator/generator) But here is the typical Wisconsin 12v neg ground external alternator wiring diagram. Your regulator has likely been replaced since Wisconsin used I-F-A-B for terminal markings.