I like my ThermoQuads because I enjoy punishment

I have had this happen on an old Monaco. The first three tips below are common issues. The fourth tip is what the problem was on my Monaco.
1. Check your float level, make sure it's not way low causing less fuel to be stored in the carb.
2. It's possible the fuel is leaking internally in the carb. Might want to refresh the carb gaskets.
3. Blocking off the exhaust crossover in the intake will lower the temps the carb sees and might slow down evaporation.
4. My fuel pump was bad, allowing the carb to drain back into the pump. After rebuilding the carb and setting my float levels twice with no improvement, I talked to an old retired Chrysler mechanic. On his advice, I replaced the fuel pump, and the problem never happened again.

Todays ethanol based fuels do evaporate much more quickly than the gas we had when the TQ was designed. If your problem does turn out to be evaporation related, I would install an electric fuel pump so you don't have to crank the motor on the starter to fill the carb bowl.