Body guys - spray gun question

Hi,

I'm a newbie at body work and have a question about spraying. I have a DeVilbiss Finish line gun using 1.5 tip, 3/8 air hose, 120 gallon 2 stage compressor. Regulator at tank and on gun. I'm shooting PPG DP50LF. I'm not getting consistent output from the gun, it surges. Any ideas on what's happening?

Thanks

if surging you mean the paint blasts out then stops then blasts out you have a ail leak somewhere. probably in the gasket between the fluid tip and the body of the gun. remove the tip lube the gasket then re tighten.
if that doesn't solve the problem the needle packing's are leaking air. this is where the needle enters the spray gun body. there will be a nut there. remove the nut, lube the gaskets inside of the nut, they might be on the in the body of the gun also, and re tighten. tighten the nuts pulling the trigger when tightening, do this until the needle starts to stop returning into the gun, then slightly loosen.
use spray gun oil when lubing. if you don't have spray gun oil use vegetable oil. DON'T use air tool oil. this can give you fish eyes.

It's more like there's less paint coming out and then more paint coming out in a steady rhythm. I'll check all of the seals.

Thanks

It has to be real tight. the fluid tip, the air cap and the nut that goes around your fluid neeedle it kind of in front of the trigger needs to be snug but not tight enough to make the fluid needle hang open ect.