Lately, i've been using spray cans and stencils for doing camo and the like on my models, but finally broke out my old Paasche kit.... I got the airflow and the thinner/paint ratio down, adjusted the needle, etc, but for some reason the paint just won't flow... I noticed a pin sized hole in the paint jar top. Do I have to cover the hole with my finger to build up a primer suction or is it something else? I've completely cleaned the handpiece inside and out but still a no go for paint flow...

Gunner,
The hole in the top of the bottle needs to be open, if too much of a vaccum is produced in the paint bottle, the paint won't come out at all. Could be a few problems with your airbrush. Pressure could be too low, optimum is around 30 psi. Could be thickness of paint, should be slightly thicker than water. If your needle on the airbrush is bent or has a burr on the tip, it will foul the air and not pull the paint out either. I would recommend fully cleaning the airbrosh again by diassembling it and checking the tip closely. Hope this helps.

Gunnerk-

I too had not used my Paasche H for a while and experienced similar to what you have described. After fiddling with thinner/paint ratios and pressure settings I finally got around to inspecting the tip.
The tip was bent.

I cannot guarantee that this will fix your but inspect the tip for irregularities as HeavyArty described.

Let us know what you find...

Look at the Needle tip & the hole in the cover. If they are damaged in any way It will cause problems. You could also try upping the air pressure as the paint may pe to thick.

Thanks guys! I looked at the needle tip and it is indeed bent a bit... Hoping that some really fine sanding will bring it back to working shape...

Replacement parts are cheap. If the sanding doesn't work get yourself a new tip combo.