tank vent

Hi, I know that's a dumb question in the sense that I should just run it with the proper part. But I have ordered one and am waiting for it to arrive, and am wondering what would happen if I tried to run the saw without it? I know the idea is to let air in and not out, but I thought that would...

Afternoon All, Trying to help out a friend with a Stihl MS200T with a broken tank vent. I ordered the parts (see attached pic) but I'm having trouble getting out the old barbed fitting that goes in the top of the tank. I tried a drywall screw screwed into the fitting and tried to pry it up...