An electric heater and switch are sealed within the choke system, with electricity supplied from the oil pressure sending unit. A minimum of 4 psi (28 kPa) oil pressure is required to close the contacts and send current to the choke control switch.
The electric choke unit is located on the side of the carburetor. The initial setting is made by the manufacturer, but it is adjustable. The thermostat housing mark is positioned opposite a specified reference line on the black plastic adapter, after which, the three screws are tightened. No normal service of this system is required, but if, for any reason, the three retaining screws are loosened, the adjustment must be made again.
The choke heater can be tested by applying 12 volts at the connection. The choke valve should reach the fully open position within 5 minutes, when the vehicle is parked.