Brinkmann upright smoker not hot enough! I have an upright brinkmann smoker, not the bullet

Question

I have an upright brinkmann smoker, not the bullet style, but the square one with two doors that i can't get above 200 degrees. My guess is that the fire pot is too far above the vents and not burning properly. I can move the fire pot down (below the vents) but then it is father from the water pan. I think it is a design flaw. Any help would be geatly appreciated.