As said check spark and you can adjust your Idle circuit but the rest sounds like your talking about Eddy carbs. No metering rods in a Thermoquad and they take some doing with jetting. JMO but haven't ran a TQ in years. They are a good carb. though. Maybe someone with more TQ experience can chime in. A bad or non seated float valve can cause some rich issues as well.
Isn't the bar that goes up and down in the center considered a metering rod on a tq? It was professionally rebuilt by our very own @Dana i don't think it's a float valve issue. It may be spark related tho.
