You basically have what is called a "cupgun" and there are a few reasons for this and it should be pretty simple to fix I want to stress that anytime you spray the paint no matter what latex-oil needs to be thinned with the compatible solvent water for latex paint thinner for oil/Alkyd by about 10% - 18% that could be the problem if you have latex in your gun but probably it has to do with the "needle seat" in the back of the gun there should be a knob to adjust the needle turn your gun on pull the trigger and turn knob till paint comes out if that wont work you may have debris in your paint that has clogged the stem pour all the paint out clean gun completely pour paint threw a strainer cone or strainer bag and be sure to thin it...