89 Bayliner with omc 3.0 with the 2 barrel Rochester carb. Had entire carb rebuilt professionally 1year ago and ignition switches over to solid state. Currently, boat will idle, but over the course of 30 seconds the idle gradually drops and drop and gets very rough until the boat stalls. It does this regardless of gear or neutral. Boat is also very hard starting when hot and requires some throttle to fire and then needs revved in neutral to stay running. Boat is easier to start when cold when choke is engaged. Idle speed screw and choke adjustment do not seem to effect the idle and starting issue. I assume it is a fuel at idle issue and want to try riching up the idle mix. Does anyone have any other ideas? Any help would be appreciated.