[simpits-tech] Driving a 28vdc fuel indicator

[dabigboy at cox.net]

I am having a rough time with something that was supposed to be simple. I picked up a 28v fuel indicator made by Liquidometer a while back. I can't find any documentation for it, but putting voltage to two of its 10 pins moves the needle. In fact, I can pretty well control the needle using 12v PWM (or variable voltage, basically) on an Arduino, with a PNP transistor, up to about half scale needle deflection. Beyond that, the needle barely moves, even with DOUBLE the voltage (30+ volts). I tried additionally putting voltage to other pins (there are a number of pins that will move the needle in much the same manner), but nothing pushes it over the magic halfway'ish point.

Any ideas? I have a gauge just like this:  http://www.ebay.com/itm/110894737604

I am about ready to gut it and stuff an air core motor in there, but I hate to butcher the gauge.

Matt