Carb Flood???

I need a little help. I have a 1977 MG Midget with a Zenith-Stromberg carb.

So when cold, the car starts when I hold the gas all the way down. It turns over and seems to stick around 2200 RPM until I gas a couple times, then it drops to the normal 900 RPM. When it drops down to 900 RPM its a pretty rough sputter idle, but after a min or so, it runs great and I can drive it around.

The problem is when I shut it off. After 15 -30 mins of being off, it won't start up again until the next day. Does this sound like its from the lines over-heating/vapor lock or the carb flooding because the float/needle?

(Hot Phoenix, AZ weather)

Thanks for the help!