It doesn't sound like a " chimney " problem
I think they are referred to as vents, but I understand what you mean.
Anyway, it's hard to tell without seeing it, but from what you said…it sounds like a nozzle orifice problem. Usually they clog and don't fire up. In your case, it sounds like your nozzle is damaged, maybe melted. I fixed mine..I think it is actually plastic…..I KNOW…. doesn't seem like a smart design. You should have it checked out and probably not use it.
They are easy to diagnose if you know how they are supposed to perform. If you need to fix it yourself…I suggest you find a friend and see how theirs works. I just ended up replacing the nozzle…easy and cheap.
I was warned against try to unclog mine with a pin, because they are so easy to damage.