MMI in Orlando? Or Wyotech?
You need to have the carb redone by an actual certified Mercury technician. Wyotech grads are a bit better than MMI grads. But with either of them, when they graduate from those schools, they are not actual certified technicians. All they have is a piece of paper that states they went to that school.
Now with the engine. If it is flooding out it is the carb or the fuel pump causing the problem. With this particular carb it is all one unit. If it was redone, it does not sound like it was done properly. Or.... and this is scenario 2. Your boat has trash in the fuel tank, and you do not have a fuel water seperating fuel filter on the engine.
When you do carb jobs on boats you have to inspect the fuel supply. Make sure there is no trash in the fuel tank. If there is, it will find its way right back into the carb again. Clogging it, again.
When ever I do carb jobs for people I reccomend (and nobody ever tells me no) a fuel water seperating fuel filter kit. The fuel filters that come on the engines are the equivelent of filtering fuel through panty hose. Not very good. The better filter kits filter down to 10 microns, and they also catch water.
That would be my advice to you. Have the carb done by an actual certified tech. Check the gas tank for trash. And install that fuel water seperating fuel filter if you do not have one.
Post back with any questions