Caper,
Most of the time when a carb floods its either caused by a leaking needle and seat valve, a bad float, or trash in the carburator. You will have to disassemble the carb to find out what it is. I would get a rebuild kit and clean and rebuild the entire carb if it were mine. The float does not come with the kit. If its the hollow metel type you can simply shake it to see if gas is on the inside. If so replace it. If its the neopren type, sometimes they will obsorb gas over time and get heavy and the only way to repair that is to replace it. Be sure to adjust the float level per factory specs.
As for the week spark you want to check your usual simple stuff first like the points, condensor, dwell, conections, moisture, coil, cap, plugs, and wires. I usually try to substitute known good parts in there place, or check it with a volt ohm meter. If that fails a partially bad ignition switch will cause a week spark. You can bypass the ignition switch with a wire, if the current gets stronger, replace the ignition switch. Hope this helps.