To amplify on my earlier post: I had tried 3 different evolutions with .2 and .4 setups and a H&S Ultra. All with several different acrylic paints, all spitting.
Since changing to Badger none of the airbrushes I have from them, Krome, Patriot or Sotar have that problem. I know all airbushes will "spit" on occasion. The badgers do too. The H&S was nearly every session at some point. What works for some doesn't necessarily work for others. Believe me. i wanted the H&S to work for me, it just didn't. Happy the that I found Badger. They work for me.