Pull off a spark plug wire and put an old plug in it,and lay it on the engine so its grounded good,and crank it over..you should see a bright blue spark every so often if the ignition system is working...you wont see a spark with every revolution,only every 8th on an 8 cylinder,since we are only checking one cylinder..
On the front of the carb facing the thermostat there are two small screws way down low on the base of it--those are the idle mixture screws..one does the right side,one does the left--sometimes they are capped off or plugged so you cant mess with them though....the idle SPEED screw is on the side of the cabb near the lever the throttle cable goes too,it bears up against that lever..