I have an americolor airbrush (the bigger black one) and it is clogged I have tried everything I've had it for 2 yrs now and have never had this problem. IF you unscrew the front cone part that goes over the needle it works but when you put it back on it back fills into the cup. You know like if you put your finger over the end bubble come up in the cup part. You would think if air can backfill then color should spray out. Does anyone have a drawing of how this type of airbrush gun is put together or anything I can try? TIA