If recleaning carbs --
No carbon in the carburetor, and using seafoam or similar isn't the right approach. Disassemble the carbs, including the domed plug at the top (idle passages underneath) -- leave linkages in place. Soak all loose metal parts in lacquer thinner along with the two carb halves. Leave the h.s. and l.s. jets in place, removing the bolt at the bottom front. Remove the float seat (soak if reuse). After soaking, run light wire or monofilament through all openings, and spray them out with carb cleaner. Set the floats level, and make sure they are reinstalled right side up. Use a new gasket between the carb and manifold. If using the black tipped float needle, use the wire clip as well. Upon reassembly, can use WD-40 on the springs and linkages (lacquer thinner will strip all lube).