Here is some more information about seafoam and it's use in ethanol mixed fuel. Basically it is fuel stabilizer that stops "goop" from clogging your jets as well as myriad other things. Draining the carb bowl is achieved by doing exactly what eherlihy said. It runs the carb dry so that there is no solvent sitting in there eating away at your rubber parts.
A carburetor is intended to control the fuel-air mixture entering the cylinder. Apparently the ethanol in your fuel is causing a problem with one of your jets. One option is to clean the carb all the time. The easier options, (which forestall cleaning) are to add seafoam, and drain the carb every time it is used.
When fuel is left in the float bowl of your carb, it sits there, dissolving your rubber parts, and creating a gooey varnish that is the premature death of many outboards. This causes the carb to stop functioning properly, so your cylinder is not receiving the right fuel/air mixture at low idle, hence it "starves" to death.