The 200t is a great saw but the tank vent is a poor design. Stihl sells a kit to repair it. It consists of a one way rubber flapper, a plastic insert piece, a short piece of tubing, and that small breather. If your handy you can repair it yourself or let the dealer do it. It will be an ongoing issue because as you climb twigs etc. will get between the air filter/ carb. box and saw body and damage the vent.