[AZKen]

Dan, I think it's a mistake to start following previous owners down the rabbit hole.
My suggestions: (thoughts)
1. Take off the electric fuel pump and throw it away. Get rid of the bottle of fuel.
2. Install a new correct mechanical pump. Keep the old pump as a spare but it could be ruptured.
3. Replace any rubber lines, replace filter. which should be just before pump.
4. After that, I will advice on a pump test before proceeding. If the test is good, then we will try to start motor. If it does the same thing, the carb probably needs rebuilt.
5. I don't know what "fill the web" means.
6. What brand is the carb? What is the number on it?
7. If you need help finding parts, you are in the right internet forum.
8. Please ask questions if you don't understand anyone's advice.
9. Lets take this one step at a time.

FYI: Your GMC is a not a "C" 1000, it's a 1000 series. "C" is for Chevy. More complete it is 1001 for short bed or 1002 for long bed.

The only one I know still available is Carter M3955. Don't buy an Ebay one.