Vent properly with this replacement breather, part number 590395, built for select Briggs & Stratton, Craftsman, MTD, Murray, Tecumseh, Toro, Cub Cadet, Lawn Boy, or Simplicity Lawn Mower, Small Engine, Snowblower, Pressure Washer, String Trimmer, Leaf Blower, Chainsaw, Generator, or Wood Chippers.