[TR] another fuel guage ?

[Randall]

> It does fall
> to empty when switch is off and also falls to empty when green/black wire
> at sender is grounded on tank ground nut.

Hmm, I think you've got the gauges backwards.  Your description of how the
"TR4" gauge acts is more consistent with the TR3 gauge.  A TR4 gauge would
show full with the wire at the sender shorted and empty with it
disconnected.  The needle would also move rather slowly, taking many seconds
to sweep across the dial (especially towards full), while the TR3 gauge
snaps to position.

Also sounds like a bad sender.  Check the resistance as Bill described, it
should rise to 90 ohms or so if you hook the lever with a coat hanger and
pull it to the top.

To make a 'real' TR4 gauge work, you only need to change to a TR4 sender
(I'm not certain offhand, but I think it will bolt up to the tank) and
provide a voltage stabilizer to power the gauge.  Without the VS, it will
read about 1/4 tank too high.  You may need to tweak the calibration a bit
to account for the difference in the fuel tank, but probably not.

Randall