It is my experiance that when the engine gets too much alcohol it runs hot, if you pull fuel back the engine gets colder. It is an oxigenated fuel. It works almost opposite of race fuel.
If one carb is working and another of the same size is not then as the other guy stated, you need to change the main air bleed to the venturi's
remember the smaller the air bleed the more fuel you will flow. ( siphon effect ) do youself a favor and get a egt sensor and guage installed.
you can tune and figure a bench mark wide open 1200 degrees. thats what we run at. Be carefull to not have too much alcohol cause it will start to burn in the header and show a hotter temp.