On Mon, 14 Jan 2019 20:51:35 -0700, rbowman
wrote:

What is the valve? One of the old style with the float on an arm? Is it
binding on the tank wall? Is it adjusted to cutoff the flow before
reaching the overflow? If a new style, is the float binding on the column?

The old metal floats on a brass arm developed a pin hole; thus not
float filled with water, just sit there an the valve never shuts off.

I've seen "sunken floats" in old carbs. They just flooded out :-)