Gaseous fuel priming system for internal combustion engines

Abstract From the Canadian patent

The priming system for an internal combustion engine adapted to operate on a gaseous fuel includes a normally closed, solenoid-operated priming valve electrically connected to the engine ignition circuit through a selector switch and the normally closed contacts of a vacuum switch when the selector switch is an "automatic" position. The priming valve controls a small flow of the gaseous fuel into the air intake of the engine carburetor. The vacuum switch has a pressure-sensing chamber which is connected in fluid communication with the engine intake manifold. When an operator moves the engine ignition switch to a start position with the selector in the "automatic" position the priming valve …