I doubt it is electrical, probably a fuel problem. Does that have the LP fuel regulator that mounts in the thermostat housing on the top of the motor? Did you replace that? If that is the type of fuel system it has, there may be a problem with the secondary regulator, that is the part that has the 2 flat diaphrams about 4' in diameter or it may have a carb with the diaphram mounted on it. Also, there is a idle mixture adjusting screw on the carb. It may be going too rich at idle. Try adjusting that screw.