I realize this isn't an easy scenario, but was hoping to get some ideas on what to check on this issue. My mechanic friend is looking at it, but he is more accustomed to working on the newer vehicles, so not sure what experience he has in the older generation vehicles.
He did check the carb and saw that fuel was going into the carb, but after it ran for a couple minutes and died, he took out the plugs to see if it was flooded and they were dry, so he is baffled over what to inspect. We're going to replace the float, seat and needle, but not sure if that's going to fix it or not. Since a rebuilt carb was installed and it ran the same way, I can't imagine it's a carb issue, so not sure where to turn to next.
Thanks for your response and I will keep all updated on what is found with this vehicle (assuming it gets resolved)!