I bought an ES-100 cup gun and It just won’t spray. I’ve made sure the tip was fully inserted. I’m running 50psi with a plenty of volume. I’ve tried both my #2 tip and a #6 tip with water. The #2 tip actually produces a bit of back pressure in the cup and pushes it off the holder. Water will spay a bit with the #6 tip, so I tried spraying some gelcoat. When you tip it forward there is a quick spray of whats pouring out from gravity and then it stops. I could take pics if that would help with the diagnosis if anyone was willing to help me. Thanks in advance.
Your probably have a o -ring missing around the brass nozzle. 50 psi seams a little low, but has been ten years or so since I last used one.
Thanks, I’ll check it. I thought I compared the pieces with the pic in the enclosed instructions. I’m hoping it is something real simple like that…
I believe they are supposed to run at 80psi. Though it’s also been awhile since I used mine.
Looking over the instructions it does say 60 to 100psi. I’ll give that a go and see if that helps. I was certain I had read 40-60psi somewhere. Old age must be creeping up on me.
We had a customer that could not get his brand new gun to work a few years ago. In that situation the vent hole in the top had not been drilled. It came from the factory that way. After he drilled a small hole all was good.
Forgot about the vent hole… Good catch 
I never cleaned mine,i just drilled it out every time