Like Ted said, spiders fill up the venturi tube with spider webs.
You can blow it out with compressed air. Like Jamie said, it's easy to take apart.
I have the same thing and I believe the oricfice is behind the venturi tube, so it's unlikely it's plugged at all, but there could still be stuff laying on it.
I keep mine in it's box over the summer so it doesn't get hogged up. I'm using it right now. It's the only thing standing between me and sofaman freezing to death while we try to smoke our cigars.
