I have a older Brison with electronic advance with polished case and it has always run great.
The problem is at idle there is no happy medium as far as a slow idle to a "little faster" idle.
I know all about how to set the transmitter to work a gas carb but even working by hand it can go from a nice slow idle and then move the arm a little....a little more.....a hair more....then like 500RPM more all at once.
Jim