What carburetor is it?
Do you smell gas when it's experiencing the symptom?
Do you have a fuel filter before the fuel pump, after the fuel pump, or both?
If you let it cool down for a while, will it restart and run normally at idle?
I like all the suggestions from others:
- fuel filter
- fuel line route away from heat
- vacuum lines
- check plugs
- check grounds (a burnt ECU? Eeck!)
- carb float levels
- clean carb (not sure if this has been mentioned yet - Also, don't forget that they sometimes have the little metal screen "filter" right inside there where the fuel line attaches to the carb)