Small Engines (Lawn Mowers, etc.): Gas cap for 125bt Huskvarna blower

Question
I have a. 125BT Husqvarna backpack blower that started leaking gas from the vent hole on the tank cap.  I purchased a new (brand name) cap but it still is leaking from the vent hole in the cap.  The original cap had a rubber gasket but it does not block the gas from reaching the vent hole.  Is the gasket supposed to cover the vent?  What is the part number for the cap gasket?

Answer
The cap will likely leak from the vent hole in the cap.  This allows the the pressure to bleed off preventing the fuel tank from expanding.  It also allows air to enter the tank preventing a vacuum from developing and starving fuel from the engine.

The gas cap part number is 695008092.

The gas cap breather is part number 531003347.

Eric