Howdy Plain Old Iron,
may I suggest you check fuel flow from the tank by pulling the fuel line out of the carby and holding a container underneath. It should pour out at a reasonable rate with the fuel tap in the full open position. If it's coming out in drips or very slowly, then it's a clogged fuel tap our fuel tap filter (the cigarette butt shape sticking into the tank from the tap assembly.
You can pull it off the fuel tap and clean it by soaking in acetone over night or get another tap assembly or test with one off a wreck or good mower.
