Thoughts on a cantankerous carburetor?

 Something rather odd has happened. I rebuilt my carburetor recently. Afterwards it was leaking out of the bottom. Not just leaking, streaming. So I adjusted it, got it dialed in and it still leaked. I decided... to hell with it, I should probably get myself a new progressive two barrel set up, and while I am at it get one with an electric choke then reroute my heater switch through the choke cable housing. (All things that have not happened yet and will not for a while... money is a bit tight at the moment.) So I rode my bike for a week or so. Then I decided to take a drive. Things went along smoothly for a few miles, then it started to act as if it had bad fuel or maybe it was drawing in air from some place. Mind you this is the original carb. On a relatively original van. Well, I limped off the freeway. Then it ran fine. When I stopped I opened the dog box expecting that familiar stream of fuel, yet there was none... it was not leaking any more. Am I correct to assume something was not seated and then it seated itself? One more thing... it has been like rain forest here in Nashville. The humidity is up in the 80% range and as history has shown me this carb. hates this time of year.
Just curious on some theory or thoughts you guys might have?

First, the stuff they sell now as "gasoline" is not that close to what the carb was originally designed to handle. A lot less 'sweet' high ends, more like diesel to keep the evaporation emissions lower. Then they tend to mix in various stuff to up the octane rating without having to 'crack' the oil again. Add in any alky and it's lower boiling point and it's amazing our old stuff even pops!

Also, while rebuild kits do come with the "wear" items like gaskets, pumps and O-rings, the castings can wear especially around the throttle shaft, and when was the last time the choke and pull-off were replaced? They get tired too. Then there are other things that affect carb operation and health. Fuel pump, filter and lines, Heat riser operation, intake leaks.

I had a carb that gave me fits the first day. The next morning it ran much better! A chalked it up to the gaskets seating and swelling with the contact to fuel.
I've had others that just wouldn't work even after doing my best possible job.

I will mention that a fuel leak is BAD and I sure hope you've got an exit plan and an extinguisher!

I have decided to retrofit the entire fuel system, I just had a rebuild kit for it and thought I would give it one last try. As far as the fuel there are a couple of gas stations around that sell fuel without the ethanol. I got about 3 mpg better gas mileage.
This van has been good to me... it's been my daily driver for several years. I am one of those fortunate folks who found an original owner van, so it really has not been cut up or abused badly. It only has 83,000 miles on it.
Now is about time for a full on restoration with some upgrades ( but that discussion is for another thread down the road a ways).
Not to worry about catching fire... she will be parked til I round up the money for upgrades. Maybe I will make a lamp base out of this old carb.

Thanks for the discussion. Keep on keeping on guys.