Ours is old and has the dual fuel carb modified for lpg. It is a very simple system - two solenoids on the Impco, one for starting?? which feeds into the base of the carb with just a small pipe, and one for main supply which feeds to a mixer ring in the carb body. It has the good old-fashioned choke on the top of the carb. One thing I am not sure about is that there is a link pipe between these two feed with an adjustable valve in it - is this for idling and could it affect starting and running? Also not sure how the starting?? solenoid connected to the small pipe operates.