I am trying to figure out why my newly rebuilt single barrel carb on my 215 pontiac is running rich. The timing is dead on, the idle is pretty steady,but it keeps loading up with fuel when idling, causing a bog when accelerating from a stop. I thought about changing the jet to something smaller but someone told me that won't fix anything because the venturi is matched to that specific jet size. He said I need a new carb. What have you guys done?