B&M Converter is bad
Just to make sure that the leak on the carb you think you found is in FACT a leak on the carb. I would suggest if possible....installing the air cleaner, putting a "straw adapter" (the little red spout attachment normally) on your can of carburetor cleaner so that you can direct the flow more precisely. and then try spritsing the area you think the leak is at.
like someone else had mentioned....being that the "leak" is near the top of the carb.....it may actually be the vacuum of air going down the throat of the carb sucking the vapor in and raising the idle causing you to think that you found a leak when you didnt.
doing the trick I mentioned with the air cleaner on may rule that possibility out.
and if you find it still leaks then COOL.....why cool?....because odds are you have found your problem....or at the very least a contributing issue.