One of the reasons I haven't moved my new acquisition home (65 Gran Sport 401/AFB)yet is a fuel leak from the carb. I've never had an AFB car before, most of my experience has been with quadrajets, so maybe some of you folks will recognize the symptoms:
Start the car cold and shut it off, no fuel leak. Start the car, let it warm up and shut it off, fuel drips off the main throttle shaft at the linkage. It doesn't leak right away after shutoff, it can take 30-60 seconds. It does not leak while running.
If it was needle and seat, I would think it was pressure related and would happen at anytime there is pressure at the inlet.
If it was strictly float level, I would think it would happen anytime, running or not.
My thought is it's a combination of float level and thermal expansion. If I'm correct, the float keeps the level below any vents, etc.. when the fuel is cold, running or not. But when the fuel warms and expands in the bowl on the recently shut off engine, the float level is high enough to allow the fuel to reach the first path out - how that winds up being the throttle shaft I have no idea.
I've got a service manual on order,but does anyone have the float level spec handy? I'll check it next week. I assume there are no tricks to an AFB to removing the airhorn while still on the vehicle...
Has anyone ever seen this before? Am i on the right track?
Thanks, Rhett