Thermostatic Air Cleaner: Operation

When the ambient air temperature is less than 50°F, carburetor intake air flows through the shroud, into a flexible connector, through the vacuum diaphragm and into the carburetor. When the temperature rises to operating temperature, the vacuum diaphragm shuts off the air coming from the shroud and allow fresh air to enter the carburetor. When the temperature is between the minimum and maximum, the air will flow through both circuits.