This cart doesn't have any switches like that. I've followed all the wires. Though that might be part of the problem as I'm quire sure this thing is not wired correctly.
I might just change it over to a key start like a lawn tractor. I'd assume the engine can idle w/o it pulling on the transmission. I'd prefer it work more like that anyway.
I ordered a service manual today and when it arrives I hope I can figure this out. The goal was to get it running and cleaned up a bit and resell it--unless my parents really liked it and wanted to buy it from me--I'd cut them a much better deal.
Mine has an aluminum bed on the back for utility use.