The "boot" is a flexible rubber coupling between the carburetor and the reed block. Instead of being rigidly bolted down the carburetor sort of floats between the reed block and the box for the air filter.
The boot usually attaches to both the carburetor and the reed block with a large hose clamp. It is possible that the hose clamp is loose or that the carburetor/boot has been knocked out of place and opened up an air leak.
i would say that its the same thing that happened to mines it some how got dirty in there and i got a paper towel and and put a little bit of gas on it and wiped the slide all around and then got some carb cleaner and cleaned all the holes in the carb and then set my idle screw slowly and thne after that it was fine(and the problem was that the dirt that was in carb was stopping the slide from going all the way down and it was flooding it so it wouldnt start.