Jeff, I had a Morse unit like that. The two levers were on separate shafts, a shaft and a counter shaft. Don't remember many details but there was no stack of washers. I think something either broke or was lost during a disassembly by the PO. The washers must be part of the fix. I doubt any parts would be available so I'd check google for images and or parts.
Might be time for a new control. There are many "ships chandlers" around and finding a used one may not be to difficult.
A few pics may ring someone else's bell.
Dave Neptune