Don, I doubt anything was "factory original." It is a repro, and so is the sending unit, I'm sure. Pete, not sure I follow. To me it looks like over "oversensitivity" problem, rather than a dead spot. Does not do it at all, obviously when it is full. Range of bounce gets greater the emptier the tank is.
A friend suggested that there might be some kind of damper, or maybe some way to restrain the movement of the float lever. Along those lines, on page 23 of the Classic Part catalog, I now see an item called a "gas tank sender unit sock filter." I never heard of this, but maybe that I s exactly what it is used for. Before I order one, has anyone used such a thing?
Harry
