[mrlmd]

I found those 2 screws holding the air box but there is no way on the planet to remove them other than grinding off the heads or trying to drill them out. Both of them are so rusted they look more like rounded rivets rather than screws and there is no way at all to grab them, so I guess they'll just stay there.
I blew out the air pipe using a small leaf blower attached to the airbox hose with the box clamped shut, and as far as I could tell, there didn't seem to be any obstruction. I could feel some air coming out underneath a little forward of the front end of the airbox, in the middle of a flat black plastic pipe. Is that the air pipe and does it go all the way forward to the level of the seat? Where is the main opening to that pipe? I'm going to try that again with a much larger leaf blower.
My cart starts and runs now with the carb connected to the closed airbox, but if I put the filter back in it dies, so I guess the filter is still wet altho you can see through it pretty easily. If it doesn't work in another day or so, I'll have to sort out another one.