Can a leaking fuel pump gasket cause vacuum leak?

I know you said you swapped out the carb a couple of times, but let me ad those 1920 carbs were prone to bad accelerator pump issues. I'll bet if you look down the carb and work the throttle slowly you will notice a lack of pump shot. Speed the motion up until you see the squirt. Do this with the engine OFF for heavy sake. I've had to work on pump linkage and travel on these carbs in years past. I was turning wrenches when these were new.