[wdhewson]

Hi. If it was a non-runner for any length of time, it may need a good old classic tune up. Start with valve clearances, as the valves need to close near perfectly to create the vacuum and pull fuel at cranking speed. Then make sure you've got a strong timed spark. And afer you are confident that these two issues are well in order, start with the carb fettling. These carbs are super precision instruments and will work beautifully, but they need to be cleaned and service almost like your a watchmaker in the days that such things kept time with low frequency mechanical oscillations.

 

[wdhewson]

Here is another twist that beat me for a few hours a while ago. Usually the fuel tap prime position draws from the lower reserve standpipe inside the tank. This lower stand pipe means a high liquid head of pressure, which might just provide enough fuel for sustained running. But still, clean and restore the system so you can make it back home without bothering your friends with trailers and vans.