[700rpm]

I have never experienced the fabled (mythical?) vapor lock, but I remember in an earlier thread two suggestions that people who have experienced it said worked for them: 1) clip one or two wooden clothespins to the gas line. I guess these would act as heat sinks if the line is getting hot. 2) Add a pint of Marvel Mystery Oil to a full tank of gas and watch for the symptoms.

But I still suspect electrical.