So I opted for the 19mm race edition because I expected to do alot of tuning...ahem, more than I knew. It is the cable choke kind, but Im not running a choke cable at the moment. I was pocking around and found that the opening of the cable entry point was pulling a vacuum! An air leak! I plug it with a small bolt and had to turn the idle up.... Question is should this thing be sucking air like it is????