take a regular kart engine and run it on alcohol
Yes you could mod/re-jet your carb to run methanol, but something you might not understand is this would not necessarily make any extra power on an otherwise stock (
'regular kart') engine. You'd need higher compression and more advanced timing to get the full benefit of switching to methanol fuel.
The biggest advantage of methanol is greatly reduced combustion chamber temps compared to gasoline, and its this cooling effect of methanol that helps your engine survive longer (compared to gasoline) when running ultra-high compression and more radically advanced timing. Its that extra compression and timing thats actually making more power, not simply the alcohol by itself.