The existing mechanical float with needle and seat would be hard to beat.
While this could be done with a solenoid and some sort of sensor to detect the fuel level had reached the appropriate level, some sort of dampening would have to be employed due to the nature of fuel in a moving vehicle.
I work with controls. Been an instrumentation guy since 1982. While it sounds like something I would do, it wouldn't be cost effective, and would add a layer of complexity that isn't needed.
Did I mention the $700 control system with a lab grade 1kΩ Platinum RTD I set up on an ice/fan fermentation chiller?
Strictly speaking, Wort doesn't need to be held at ± 0.05°FIt could have been done for $8 for controls.
If you find that you simply have to do it, be very careful. There are few intrinsically save devices with a click to buy button out on the internet. While the environment inside the float bowl isn't necessarily housing an explosive A/F mixture, all it would take is a spark to test that assumption.
CJ