I think you are on the right track......I would check for spark at the plugs, the points, and maybe replace the condenser. The condenser on my 3a was rubbing against the point cam and it nearly wore through!
But it still might be a fuel feed problem.� i.e the float bowl fills slowly, just enough to run it for a short time but not fast enough to keep it running.
Double check the in-line filter for flow if he has one..
Will it re-start after a short time?
It seems to me there is a small cylindrical filter screen in the W-O carb. I'd have to look at mine to find it, but it may be clogged...I know it's accessible from the outside the carb. The jeep is not here or I'd go look.....you may already know about it if you are able to bush the throttle shafts....
So I would also check float height, or look for a stuck float, or a clogged float valve...
Also check the crankcase oil for the smell of gas...if the seals fail in the double action pump you can get gas in the oil....
That little filter screen is under this large brass plug....but I think it is in the accelerator pump circuit...
And don't forget to check the fuel level in the tank..with a stick!!
