HF sandblaster

I purchased a barely used Harbor Freight free-standing sandblaster cabinet from my boss here at work. I have it stoked with fresh walnut shell media. Now, this thing, when working, will peel about two square inches of paint or rust in a few seconds. Then it just seems to be blowing air and walnut dust until I pause, wiggle things around, etc. The feed hose feels full of media, and while it does kink a little, seems to be fairly free flowing. If this thing would blast consistently, I'd be done in a flash with the pieces I'm working on. Air pressure is at least 80 psi working pressure minimum so that's not an issue. Anyone else have one of these units and figured out a workaround?