302 engine. Autolite 2100 2B carb. Relatively minor problem, but annoying. After sitting 48 hours most of the gasoline in the fuel bowl has disappeared, which makes for longer cranking when starting the engine. When I removed the carb for a bench inspection, the fuel bowl was nearly empty & there was a thick, almost dripping coat of gasoline on the throttle plates. More on one side than the other. The power valve’s vacuum compartment is completely dry. Thinking it still might be a problematic power valve, I replaced the power valve and set the carb over a container to check for leaks after I re-filled the fuel bowl. This again is a bench check, not on the vehicle. No leaks at all as far as I can tell. The only time I observed a visible leak during the bench testing was when I overfilled the fuel bowl, more than the float valve would allow, which caused gasoline to leak from those donut shaped things in the venturi. But the fuel level should never get that high during normal operation. And even if that is where the leak is, such a leak wouldn’t completely empty the fuel bowl would it?
The only other ideas I can come up with
Maybe the new power valve has fixed the problem.
Maybe the gasoline is boiling out after the engine is turned off.
Maybe there’s a problem with the fuel bowl venting which is creating some sort of siphon effect.
Ideas what to check next?
What about the accel pump? Anyway a problem w/that could cause this?