motor getting to much gas

[boatingDad]

I have a 1996 90 hp Evinrude that leaks fuel when its sitting. The gas appears to be leaking out of these little ball cocks near the cylinders, I think. The boat runs great at higher speeds but at a troll it gets gassy smelling and smokey. Stays running but seams to get to much gas. Wondering if its a fuel pump problem or if there is a carb. build up? I appreciate the help.