Weird /6 BBD issue (internal flooding?)

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Scooper

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Ok, have had this BBD for some time. I rebuilt it, also drilled out + rebushed the throttle shaft, choke shaft, and pump shaft holes. Everything is solid, smooth action with no play.

Problem: I had never gotten this carburetor to work correctly in the past. This time I have attempted to install it, as usual I could not get it to idle worth 10 cents. It acts like it wants all of the idle air. All of it. Like, take the screws out and it would be a happy hobbit. At 3000 rpm.

That tells me its rich.

When I unplug my vacuum gauge from the small manifold port on the base (below and right of the right-side idle-air screw), gas dribbles out. But not constant. Few drops, and thats it.

Is it leaking internally from someplace? Anyone have any idea/experience? Do I just suck at carburetors?
 
As an addendum, I pulled the top of the carb body off, and, the floats appear to be doing their job. Fuel is stopping at the needle+seat. Granted, that is just by eyeball.
 
Sounds like an internal air bleed is stopped up. Have you taken mechanic's wire and run it through ALL of the internal passages and holes in EVERYTHING? I use a welding tip cleaner set. Works good.
 
I believe I did in the past (I have several sets of those tip cleaners), but am not 100%. I can certainly add that to the list of things to try when I pull it back off tomorrow.
 
Update:

Pulled the carburetor off.

FAILED TO PREVIOUSLY MENTION THAT PCV VACUUM WAS WEAK.

This is relevant, because, I am not seeing any provision to feed the PCV port vacuum. There is no corresponding hole in the manifold, so, the gasket (which had a hole) was sealing to a flat surface.

Would that create excessive vacuum in the carburetor and force it to draw fuel from any/everwhere?
@RustyRatRod
 
Scooper said:
Update:

Pulled the carburetor off.

FAILED TO PREVIOUSLY MENTION THAT PCV VACUUM WAS WEAK.

This is relevant, because, I am not seeing any provision to feed the PCV port vacuum. There is no corresponding hole in the manifold, so, the gasket (which had a hole) was sealing to a flat surface.

Would that create excessive vacuum in the carburetor and force it to draw fuel from any/everwhere?
@RustyRatRod
Click to expand...
"Corresponding hole in the manifold" Can you elaborate? The port for the PCV is on the carburetor, not the intake.
 
RustyRatRod said:
"Corresponding hole in the manifold" Can you elaborate? The port for the PCV is on the carburetor, not the intake.
Click to expand...

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that is correct gasket 3/8 thick your carb already has notches. A bbd with out notches will need notches in gasket green arrow
 
When pvc first started slant six had hole in manifold and hole in gasket for one barrell, changed as time went on
 
That gasket was leftover from when I was running a WCD on it. WCD worked flawlessly, but had no provision for PCV.

Changed to the correct gasket. PCV vacuum is good.

No change in operation. Still wants 1000% of the idle air at a billion rpm. Still dribbling gas from the lower vacuum port after cutoff.
 
Many different gaskets the one in picture is the right one. Red lines point to idle down channel, holes in right spot. wrong gasket blocks those holes. Only thing left to idle on is main circuit, thus high speed

bbd red dots.jpg


red arrow idle.jpg
 
Gaskets in picture wrong one idle holes in wrong spot . In one picture you can see idle srews, look close your carb may have brass idle restrictior,if it does make sure there clean
 
Swapped back to the WCD. The only two BBL in the universe worth 10 cents.

Tried everything suggested. Blew the whole BBD back apart. Finely adjusted the floats. Snaked out all of the vacuum lines, ports, and holes. Lot of in depth cleaning. Made a new lower body/housing gasket. Swapped in brand new check balls. All of this in addition to running the correct base gasket.

Zero change whatsoever.

Officially swearing off BBD's. They're junk. Have had two and never was able to get either working right. I pulled this WCD off a scrapyard Rambler that had been sitting for 30 years with a mangled/open hood and worked without even 'popping the cork'. Even the accelerator pump was good.

If anyone wants this piece of junk BBD, just DM me an address and you can have it. Might be good for parts. If I keep it, it's liable to some 'excessive' percussive maintenence courtesy of my 5lb sledgehammer.

16435652246046413959570050185117.jpg
 
You’re barking up the wrong tree with the gasket idea. The screw you mention is for idle FUEL mixture. Which is air and gas. What typically happens is the Idle feed restrictors are sized too small for today’s fuel. That is why it wants the screw backed out all the way. When this fails to run the engine correctly, the mechanic will often turn the idle speed screw in until the carb idles off the main circuit. Also if your timing is say 8* btc or later you will amplify the problem significantly.
 
Dana said:
You’re barking up the wrong tree with the gasket idea. The screw you mention is for idle FUEL mixture. Which is air and gas. What typically happens is the Idle feed restrictors are sized too small for today’s fuel. That is why it wants the screw backed out all the way. When this fails to run the engine correctly, the mechanic will often turn the idle speed screw in until the carb idles off the main circuit. Also if your timing is say 8* btc or later you will amplify the problem significantly.
Click to expand...

Question/problem of the hour: that doesn't explain why the WCD has zero troubles nor does it explain the gas dribbling out of the manifold vacuum port. This BBD (flooding internally) does.

You have to realize I have tried every suggestion posted. The gaskets were merely one of them.

For posterity's sake, I did also try adjusting the timing. However, this particular /6 likes it's distributor in exactly ONE spot. No matter what carb it has sitting on it. Any movement from that spot in relation to timing and the motor pitches a fit.
 
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