Well...good to hear it's only a carb problem. Rebuild kits for the 4180s are still available (and not too expensive), so I bet that the 2150s are still out there, also. I had a buddy teach me to rebuild them a few years back...best 3 hours I've spent on my '83 (which wasn't running when I bought it, or trying to).
Here's a site with good info on the carb (and rebuild stuff, too).
http://home.earthlink.net/~bubbaf250...rb/carb03.html