Automatic Choke System

A 2-element heater is used to heat the bi-metallic choke coil causing it to relax and open the choke valve. Current to the choke assembly is supplied through an oil pressure activated switch so that the electric choke is activated only when the engine is running. One heating element is in operation whenever current is supplied to the choke and the temperature inside the choke housing is below the calibration value.

This element heats the bi-metallic coil and also heats the plate above the switch pocket for the second heating element. When the switch pocket reaches calibration value or above, a bi-metallic switch then supplies current to the second heater connecting it in parallel with the first heater. This switching function causes the choke to come off at a faster rate with 2 heaters engaged than with one heater engaged.