Choke Thermal Vacuum Switch (CTVS)

Used on 250" 6-cyl. engines, some 400" V8 engines w/2-Bbl., and all 4-Bbl. carburetor engines except Omega 350" V8 engine. Application gives richer choke operation when engine coolant is less than 57°F (most V8), 60°F (6-cyl.), or 62°F (400" V8). Carburetors are equipped with 2 vacuum breaks. Choke thermal vacuum switch controls vacuum to carburetor, front or auxiliary vacuum break. When engine is started and coolant temperature is greater than specified, both vacuum breaks pull choke to leanest position. If coolant temperature is less than specified, choke TVS closes preventing vacuum break from pulling, which gives a richer start and improved cold driveability.