Screw in fuel sending unit
 

I have a 2000 38 Fountain Lightning and the port fuel gauge does not work. It looks to be a screw in. Part number 7826 240/33 . Can not seem to find this number for replacement.

It might be easier to figure out what the resistance range of the sensor is and just find one that matches. Most resistance sensors are 0 to 150 ohms. You could get a cheap rheostat from radio shack and sweep it from 0 to 150 ohms and check your gauge function. I know my Gaffrig fuel pressure is 0 to 150. You could just get their sensor.