Why!...WHY!...

As Karl said, the needle has slipped back from the nozzle. Loosen the chuck that holds the needle and push it forward so that it just seats on the nozzle. That's a common problem and someone finds out about it about once a week here.

18co, did you loosen, or remove the needle for cleaning, after the first colour? If so, chances are that the needle is not fully seated against the spray tip, allowing paint past, even when you haven't pulled the trigger back.

Try loosening the needle chuck, and gently pushing the needle forwards until it meets resistance. then tighten up the needle chuck again and try spraying.

Best of luck.

Karl

I'm not familiar with your AB, but any single action AB releases paint & air at the same time. The amount of paint will depend on how much you have opened the needle. Only double actions allow you to control the paint flow by pulling back on the trigger to open or close the needle.

Regards, Rick