While running, the vacuum at the carb hose nipple that goes to vac line 28 is zero, is that correct? This is the line that goes to the secondary diaphragm and the thermovalve. I put my vacuum pump on the nipple and air flows freely through the carb and the secondary diaphragm functions and holds vacuum. The symptoms: 1:On cold start (less than 40 deg air temp) the idle remains high even after the engine is hot. 2:Hard hot restart (80+ deg. air temp) after setting for 20 minutes. I'm suspicious the choke pull off (replaced) is not working, bimetallic seems to work ok.
TIA for any help

 

I don't have the vac line 'map' in front of me; however if you pinch off both vacuum lines to the choke pull off the plate should open.

 

Follow Up
Switching to ethanol free 87 octane fuel solved the starting problems. Runs like new.