[TR] TR3A Fuel Guage

[terryrs at comcast.net]

Although I had my fuel guage, along with all my others, rebuilt at MoMa's, I confess they came back unhappily shabby.  The speedometer wobbles, none of the needles were touched because they're as rusty as when I sent them, and now the fuel guage reads dead empty most of the time, although very rarely it pegs to the other side.  I installed a new sending unit a couple of years ago.
I suspect the guage, but to rule out the sending unit, would it work to hook a variable pot to the fuel guage in place of the sending unit, then slowly adjust the pot to look for movement of the needle?
Maybe I'm overthinking and there's an easier way....
Terry Smith, '59 TR3A
New Hampshire