One thing to add:
I was reading about a Briggs and Stratton alcohol conversion (for karts), and the article explained how you needed about twice as much fuel vapor exiting the carb to run properly (sounds similar to the jetting suggestions above).
The other thing that the article mentioned was that you had to run the engine dry; close off the fuel, and run the machine 'till there is no fuel in the carb or cylinder. The author also suggested that you then hook up a small bottle of normal fuel to cleanse the alcohol from the system, but that sounds like a lot of trouble (especially since you'll be pumping in twice as much as you need).
I believe that if you _don't_ do this, the alcohol will eat at the seals and gaskets. I'm considering building an alcohol engine, and part of what I'm planning is to have a small reserve tank of gasoline to use when shutting the machine down.