The latest episode: I dipped the float into my half-can of Red-Kote gas tank sealer.
If anyone here is as old as I am you might remember from your youth a sort of drug-store toy known as "Plastic Bubbles." Cost about ten cents and consisted of a tiny tin tube of a gooey evil-smelling plastic gel and a thin plastic tube. Apply a bit of gel to the end of the tube and you can blow long-lasting bubbles that sort of floated. If you inhaled while producing your bubble you'd experience the crystal mysteries of solvent poisoning.
Anyway, that's essentially what Red-Kote is. I recognized the distinctive odor 65 years after I'd last experienced it.
Before submerging it I removed the needle from the float so that the needle hole would fill with Red-Kote. Then I blew the stuff out of the hole and let the float dry overnight. The needle fit in fine, and I adjusted it to what I think are factory specs: 14.5mm from needle tip to float surface.
I haven't installed the sealed float yet because I wanted to see how it floated. So in a jar of gasoline I found that the float, including the needle, floats with a freeboard of about 1/4 the height of the float--that is, it floats with about a quarter of the float height above the surface of the gasoline. This is a good deal higher than the level I'd had before, which was that the top of the float was level with the gas in the float chamber.
I'm leaving the float in its jar of gasoline overnight to see if it wants to float lower, which would indicate that the float is once again absorbing gas and getting heavier. Its level had not changed over twelve hours or so, so I'm optimistic.