Why would you take it apart to clean when spraying Future or any acrylics? I run some Windex through at high pressure (50-60 PSI), then clean that out with distilled water. I have never taken my airbrush apart to clean it in 8 months.
The sputtering is caused by one of two things. Either there is still something blocking the air passage in the head assembly. Or the Teflon Needle Bearing is damaged or missing. If the 200 series had a head washer like the 100/150 series does I would suggest that.
See the parts list from Dixie Art for the
200NH it's part #50-046 and they recommend that Badger replaces the part.
I hope it's just some cleaning issue. I would hate to see you have to ship off your AB so soon after getting it.
edit: I forgot to mention that you should use beeswax to reseal the threads on the head assembly. You may be getting air leaking through there and that would cause sputtering too.