Stop in for a cup of coffee

WV64Signet said
It had stopped working prior to the untimely demise of the 225. Engine wiring is still incomplete so I've not had power to the system in a year

yeah, before anything i would just try grounding the sending wire and see if the gauge goes to full then you know if it's a issue before or after the sending unit... also sending units can lose their ground and the gauge won't work which is the most common cause of it, to the point they made this clip to jump over the rubber hose on the sending unit so it would have a ground to the metal fuel line.