Thanks for all your ideas. Once running, it runs very well with no hesitation hot or cold. The weber has a return line which is connected (like the stromberg). The supply and return lines are physically located higher than the fuel bowl.

I drilled a small hole in the gas cap. It had no effect other than preventing a buildup of vacuum. This would suggests that the fuel bowl is being emptied for other reasons - not vacuum.

__________________
Dan
1981 240D
1987 300D Turbo
1973 220
Das Beste Oder Nichts