OK, it's fixed.
It was indeed the spray nozzle.
The gun shoots water just fine now, even though there is a slight flutter.
The flutter is most likely caused because I didn't tighten the nozzle
enough, (from the DeVilbiss manual), I was just to much in a hurry to test
Will adjust and try paint next weekend.
Thanks again, to all that gave me help with this problem. Ten years ago my
eye sight was better and I would have caught that crack in the nozzle.