Technical 8ba only idles with wiper vacuum line detached

So Thursday I had taken my 1950 Ford custom deluxe down the 301 from Pennsylvania to Virginia to visit a friend. It did the trip just fine, cruising along at 55-60 no problem, even going up to 75. Friday we took it for a spin, no trouble. Today we took it to a car show and it was fine (won an award for "farthest traveled"). While at the show I had it running and it was smoking and burning oil like it usually does (it's a flathead, duh) and a passing man said it was probably rich. I should have known better because I had installed a pertronix coil and electronic ignition and adjusted the carb to the spec in the factory shop manual about a year and a half ago, even had it looked over by a pro and he said everything was fine and it was. But like an idiot I started to adjust the idle fuel mixture, and no matter how far the screws were in and out it made no difference at all. So I figured I'd lower the high idle while I was there and I did. Everything was fine. So we're driving back to the house after the show and it stalls at a couple stop signs, so I re adjust the idle speed back to where it was and I notice that it's loping/ surging, but still running. So I go to adjust the mixture again and nothing happens, no matter how far you turn the screws. I shut the engine off and examine the screws, and they both look fine. So for curiosity I start it back up (still loping) and remove the wiper vacuum line (it has a splitter on it for a wolf whistle) and it immediately starts running perfectly, purring like a kitten. So I re attach it. It sputters, surges, and eventually dies. So I start it back up, putting just the wiper vacuum line on (no splitter) and it dies again after surging bad. This is odd because before it would still run with the vaccum line attached, just not well, now it doesn't at all, just surges till it dies. So I try to attach my vacuum gauge and of course that doesn't work because it just dies as soon as it's attached. Worst case scenario I can do the 7 hour drive back on Monday with the vaccum line off, but I'd really like to resolve it. I assume either the power valve is broken or somehow the screws jammed something in there, causing the jets to get stuck in the permanently "all the way in" position. When the vaccum line is off and you screw it in all the way it acts like it normally would when adjusting the carb, sputtering until you turn it out a turn. That's just my theory, so I value you guy's input greatly. I've attached 2 videos, one of it running poorly, and one demonstrating the vaccum line debacle.

 

Check your float height. If fuel is dribbling in, you won’t be able to adjust the idle mixture.

 

Yuppers, running too rich on the idle circuit and pulling the line off causing what is basically a vacuum leak that leans it back out to where it wants to be. I'd try shooting some carb cleaner down the idle air bleeds in the carb throat and pull the mixture screw and shoot some carb cleaner though them to see the air passages are plugged up.

If that carb is a Holley 94 like my 8 BA came with it also has a power valve that might be leaking.

 

my first thought was power valve also but check that air filter to see if it is real dirty.

 

Thanks that's probably it.

 

When your idle screw adjustment has no effect on the idle you have a vacuum leak somewhere. it could even be at the intake gasket.
Use an unlit propane torch, start the car and run the torch at suspected areas. A vacuum leak will pull in the propane and increase your idle.

 

The old stuff is reliable, but are not set and forget. They require regular maintenance.
Sounds like it's getting fussy. Check all the suggestions here that are possible solutions to it running too rich and not being able to adjust.
Don't just limp it home with the vacuum port open. It could easily cause damage!

 

My vote to leakin power valve . Todays gas is hard on older produced parts .

 

Yeah I just raised the idle some and it's back the way it was. I think this was already an existing issue but it was unnoticeable because the idle was set high enough to negate the effects of it. I can't take the carb apart right now so I'll have to wait until I get home

 

Let us know what you figure out when you figure it out.

 

I imagine it's probably a combination of something being gunked up and the power valve being worn. But everything is back to the way it was when I drove it down here so once I get back tomorrow I'll work on it some. Like I said everythings been fine with it and it runs and drives strong but it would probably be even better.