Alright, that's progress... I think.
. That little rod on the driver side of the 4160 serves to
close the secondaries, should they be open, when you lift your foot off the throttle. There should be no binding, tightness, or stiffness. Having a little "looseness" to it all is normal. To diagnose your fuel leak you should use ultraviolet dye and a black light. Do not be misled by fuel leaking out the throttle shafts because you squirted gas on to the primary butterfly valves while you were testing for binding over on the driver's side linkage. Make sure your bowls are filled up normally (just by running the engine and then shut it off). Put about an eye dropper full of uv fuel dye (available on Amazon) down each vent tube of the carb. That's one for the primary and one for the secondary. Then DO NOT TOUCH THE CARB and under no circumstances work the throttle to induce a squirt. Watch the carb for the next couple of days under the black light. Look around the bowl gaskets, metering block gasket, the little cork gasket around the idle mixture screws, and everywhere else. Then report back.