The air / gas mixture is electrically manoeuvred. This makes many benefits: You can control the throttle valve more precious than with wire, place the control there a wire could not be led and you can connect a lambda censor to the circuit that regulates the air / gas mixture automatically.
The regulating system that I use is from my previous wood gas car and consists of a lambda censor, circuit box, control panel and a RC-servo (like the ones on radio controlled cars). You can choose automatic lambda regulating or manual regulating with a knob the control panel.
The automatic lambda regulating means that the system measures the amount of oxygen particles in the exhaust and regulates the mixture.
The lambda censor knows if it is too much or too little oxygen and sends out a high or low voltage. The circuit then measures the voltage and starts closing or opening the air valve.
Today I rebuilt the control panel so it will fit on the gear stick. I used corrugated cardboard to make a model and form the panel ergonomically for the driver. I drilled a hole in the panel and welded a pipe with screws on, so that I could lock it on the gear stick. The wire on the panel is for idling speed. The round knob is for adjusting air mixture manually and the switch is for choosing manual or automatic mode. Led 1 is for power, 2 for automatic mode and 3 is reserve.