Gets hot and stalls out

Post #119 asked about the troubleshooting results. I see you're running in several directions. You really need to focus on why the no-start. Does it have spark? Does it have fuel when you rock the throttle lever? After you fix the main issue you can start dinking around with other things.
I appreciate the advice but I’m really not. I’m focused on the fuel issue, so I’ve put the spacer in and am redoing fuel lines. When I started it the day before yesterday I checked the fuel level in the carb via the sight glass (was where it should be). I’m waiting for a part (arrives today) so while I’m waiting I’m exploring other things that might be a cause, mostly because I’m still convinced that the alternator has something to do with it. Again for clarity: everything started after I replaced the alternator, and I just don’t like coincidence. So, heat issues first (fuel lines, new filter, new coolant), test, move on as necessary.