1994 36v Marathon controller testing

[miller1d]

I am repairing a 36v cart for a friend, he brought it to me with new batteries, but would not move. I found some wiring issues where someone had added and moved wires around the FR microswitches and fixed those and verified the wiring diagram correct now. He assumed the controller was bad and brought a spare used one he had no history of. I tested the Pot and found it defective and replaced it and tests zero to 4.8 now (50% in rev) so it should be good. Battery pack at 38.1 volts. The cart would not move with the 1204-001 275 amp controller he had on it, and we put the other 124-027 400 amp on the try it. On the floor, it barely crawls slowly in forward. Battery pack drops around 1/2 volt during that. It will not move in reverse. On jacks wheels off the ground the pedal goes half way down (?) before wheels turn and they turn both reverse and forward. Test neg battery to M-, click pedal, 38volt, push to floor, zero. I checked cable ends and connections, and assume it must be the controller? how can I verify the proper controller that should be on it since it appeared someone had been changing them prior as the wires were marked with tape. Thanks in advance!

[miller1d]

It is a 1994, I think Marathon due to the split seat backs?

[miller1d]

Finally figured it out! Realized a previous owner trying to repair it installed a Regen motor instead of a Series motor. Switching motors hopefully fixes it now.