So I have a 83 40 mariner Yamaha engine. It runs rough and weak on and off from idle to plane. On Plane it runs smooth. it only does this sometimes and there seems to be no pattern to it and after planed it smooths out. Both cylinders are firing I pulled wires today while it was doing it. Both carbs are rebuilt and the tank is clean, blub is tested and good. If you choke it a little it floods out, so I have pretty much ruled out gas. any ideas would be great. Also on the carbs the one skrew they have I am assuming is idle air what is a good starting point for that?
