I'm having a similar problem with a Badger 150. Up until a few weeks ago, it usually worked beautifully. But for some reason, lately it's done weird things like refusing to spray blue paint for more than two passes (up, down, no paint -- run the needle in and out --- up, down, no paint -- rinse and repeat), or working terribly with one color, working well with another, and then being somewhere in-between for a third -- and paint brands don't seem to matter (Tamiya, Polly-Scale, G-S, Accu/ModelFlex, etc.). Because the paint sometimes splatters, I thought I might've split the tip/nozzle, but that seems okay.
Tonight I was able to successfully shoot a part with blue paint before it quit, so after a rest I tried to paint a caboose. The paint tended to start out too wet, then quickly started drying on contact, before finally cutting out completely. I clean the stupid thing religiously, but I've noticed some paint clogs in the nozzle lately. So, will I have to just disassemble the poor thing and try to reassemble it, or is it time to bury it and start using a Paasche or Iwata?