That you needed a new mark on the balancer is a concern. How far off is the factory mark?

Try popping the hood when you shut it off, let it cool down faster see if it helps.

I had a couple of cars that did this, the problem was heat. The fuel in the carb bowls would boil, and the pressure would force the fuel out flooding the manifold. If the car sat long enough for the fuel to evaporate it would start fine. Otherwise I would need to crank it with the accelerator to the floor for five to ten seconds to clear out the fuel.