I imagine many of us here on Permies are old
enough to remember the old style 5 gallon or any size portable gas tanks that worked. At some point in the not too distant past, regulations changed and manufacturers of new portable tanks came up with clever, but not very functional in my opinion, ways to meet new regulations in place. I'm referring to the kind that have a push button on the pour spout, or the kind as shown in the first picture, that has this clumsy contraption of a filling neck where the little red buttony tab gets pushed, the entire tank is lifted upside down and placed as such in a filler opening that a small tab on the filling neck rests on the edge of the
lawn mower fuel tank for example, thus depressing the telescopic neck allowing fuel to flow. I imagine that may be confusing for one to imagine if someone has never used one of these poorly designed portable gas tanks.
My brother surprised me the other day with pieces to convert a portable gas tank and make it like the old kind, with an unobstructed neck and a vent for the opposite side of the gas tank. I had no idea these things were out there. With a 1/2" drill bit, I put a hole near the top of the tank for the little yellow vent, and simply removed the original neck and screwed on the new one. Easy peasy, and now I have portable fuel tanks that no longer cause frustration.