#1033 Transformers

Are you sure that your meter is working correctly?  Not sure about U to C, but I've used 1033s for years and they have been very reliable.  U to A should be 5-16V and U to B should be 0-11V.  Check your batteries in the meter.  Beyond that you would have to take the cover off and see if a previous owner(s) changed something.

Put a load on the transformer when taking the reading. On old style transformers I prefer an analog meter.

@trainman129 posted:

Terminal U to A gives 8.7 volts. U to B gives 4 volts. U to C gives 0 v, then 10.3 V just advancing the handle a bit. Full on gives .6 volt. Backwards from what it used to be...

You should be checking voltages in reference to the "common" post "A".  The throttle movement will be in the direction you expect when you do it this way.

The "U" post is connected to the transformer wiper arm, direction, and whistle controls, so you absolutely don't want to use "U" as common on a common ground layout, or you will get some unpredictable operational results.