I'm no carb expert but you may have an obstruction in the idle circuit on that side. May try removing the screw and spraying some carb cleaner in the hole and down any of the small air bleed holes at the top of the carb. You may also have the idle screw turned in enough that its running on the main circuit. However if this was the case your drivers side screw wouldn't likely have much effect either Maybe some more experienced carb guys can chime in.
Good luck!