Model B Carb Issues

[TinCup]

So as one of my Covid-19 therapy projects I rebuilt and restored 2 Model B Zenith Carbs. I actually really like them. They run and idle well and the transverse mounted float helps with stalling at sudden stops. Both of these perform almost the same and both have the same quirk. From start to about 180 degrees engine temp they perform flawlessly. Once the temps get up the carb stutters when taking off from a start and require more GAV adjustment. I was surprised because before the summer temps hit I had driven these carbs many miles with no issues. I start the car with about a quarter turn of the GAV and almost closed after the car warms up. If the car temps stay below 180 it will run all day like this. After the temp starts to exceed 180 then it acts as if it starved for fuel and I must open the GAV at least a half to three quarters of a turn to get it to smooth out. Stock A Zenith we all start with a quarter to a half open and then close as the car comes to temp. If I run a stock A Zenith this behavior is not repeated.