Just some thoughts and info about gas tank grub screw venting:
AND those itty bitty screws inside the vent tube are called
grub screws and if you are ever replacing the vent tube itself and using the old grub screws you are not suppose to twist or thread the old grub screws into the tube, push them in the tube so as the tank vents air around the threads. (and sometimes even pushing the grub into a soft vent tube will result in non-venting later)Twisting them in will sometimes result in the grub screws cutting threads into the tubing and non-venting or reduced venting will result.
A test with a hand held vacuum pump will get you some surprises about grub screws installed into tubing as vents.