Honda 75-90 hp Carburetor Conversion 2001-2006

After researching the part number details of these two engines, I find that the only difference in the basic engines are the carburetors. All other pieces, such as manifolds, gaskets, spacers, linkages, camshaft, displacement, head + valvels, etc. are the same. If you wanted to increase the 75hp by 20% (to 90hp), you need more than just jetting changes, i.e. the entire carb set (especially since the cams are the same). Even though the intake manifold and all mounting of the carbs is the same between these (2) engines, the carbs on the 90 must have larger venturi ID's than the 75. Ergo, the 75 is 'detuned' by restricting the carb throats.

1. Does anyone know of someone that has experienced increasing the power of the 75hp by simply changing the carb set, and
2. Know where a set of 90hp carbs can be obtained? (if the online parts stores have them, the price is is about $1,200 for the set. )

Thanks, and thinking ahead to summer -
E.T!

Do you guys have any sugestions on a 2006 75hp Honda as far as owner replaced carbs but it still runs rough. We think they left gas in it all winter. Can it be cleaned or new carbs needed?