I just purchased a Bayou 300 (have no idea what year it is as I don't know where the ID numbers are). I think it is a 1991. The previous owner gave up on it as he could not get it to run right. The issue is that in order for it to start and run, I have to put my hand over the intake of the carb. I have to completely cover the inlet to get it to start, then continue to block about 90% of the inlet to keep it running. The previous owner put a new carb on it and it does the same thing. I don't see any leaks around the carb. boot and all the bolts "seem" tight.

Any suggestions as what this might be? Thank you for your help.
Bill