help with Badger 200 please

Dear all,

I'm having some periodic problems with my Badger 200. Once in a while the paint will refuse to shoot up the container tube and into the air mix, hence nothing comes out when I try to spray. I've checked the paint tube and container cap, they're not clogged. I tried cleaning the airbrush with lacquer thinner to no avail. Interestingly enough, when i put the airbrush under running water, and have the paint input nozzle (where the paint tube is inserted into) facing skyward, water would have no problem running through the inside of the brush and sprays out properly. It's only when I use the paint container it doesn't work. Strangely, this problem mysteriously goes away after a couple of days, until it mysteriously comes back again.

I am so tempted to just replace this with a gravity feed airbrush. Am I doing anything wrong?

Thank you

Terry