Yep, that's what I was afraid of. I'm tempted to buy a Carter rebuild manual I saw on Amazon, just to see if it can shed any light on tell-tale signs. For instance, this carb has an extra port which is not present in my other carb near the front left mounting hole in the base. I've already downloaded the info you referenced - that's what got me through most of the initial setups and adjustments last weekend (thanks).

I'm convinced that a bit more tweaking will take care of the choke issue. I just haven't had time to sit down and really analyze what's going on. At this point, I'm leaning towards the linkage rod being the problem more than anything.

Choke pull off part numbers given by O'Reilly's for '78 Volare six cylinder:
Walker - 101-554
Borg-Warner - VC237 (two mounting holes in picture)
Borg-Warner - VC668 (three mounting holes in picture)

And by Advance Auto:
Sorensen - 779-6066

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

When using a vacuum gauge, where do I tap in? I was coming off the "tree" on #6 intake runner and getting a steady 15 in., but I've read that it's not the place to do it. I've seen pictures of the Carter BBD with a tee fitting in the rubber tubing that connects the choke pull off to the back of the carb. Should I insert a tee in mine, or is there another appropriate place already available? Would I expect the vacuum to increase over the 15 in. I was getting?

And is the baseline reading taken at curb idle speed (750 rpm)?

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

Choke pulloff is a good place to tee in, or temporarily disconnect the choke pulloff. Check your vacuum at curb idle with the motor warm.

No need for a tee. It's the little one on the bottom right side that you can barely see sticking out. It should be facing toward the battery when in the car. Should have it capped at all times other than when you have a vacuum gauge connected to it. Make sure you have the hose on your vacuum gauge pushed on it tight or else you can lose 1 or 2 hg by it being loose.

http://app.infopia.com/img/image/fp/VPI ... 3/size/250

Reed, you da man. Using your very explicit explanation of the choke and choke pull off functions, I was able to determine that the choke arm was not pushing the choke plate completely closed. As a result, the fast idle cam was not rolling over far enough to allow the fast idle screw to seat on top of the highest lobe. I also changed out the linkage rod on the choke pull off to the shorter one from the original carb (should have done that when I swapped out the bad choke pull off).

Now, when cold, pressing the accelerator pedal sets the choke, and once the engine starts, the choke pull off draws the choke plate back to the proper position for the engine to warm up. Tapping the throttle releases the choke and fast idle cam, and drops the engine speed down to curb idle.

Yee Ha! A few more tweaks here and there and Aaron will be back in his Dart in no time - and I can have my truck back. Jake, I'll look for that vacuum port you mentioned. I think it's probably the one I said was the only one the original carb did not have. It currently has a rubber cap on it.

Thanks for everyone's great help.

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

Happy to help, but make sure the carb is adjusted properly:



http://www.slantsix.org/articles/choke- ... adjust.htm

The rebuilt replacement BBD I installed was running great - for about a week. It was running good at curb idle, at part throttle stop sign to stop sign, and at highway speed. It would sit and idle all day long if I wanted it to. All I needed to do to get it finely tweaked was to set the valve lash and a final idle mix adjustment. Until Friday...

After work, I cranked it up and let it warm a bit while I visited with a co-worker in the parking lot. I left the office, made several slow approaches to intersections, a couple of stops at some stop lights, cruised down the highway at 70 mph, took the off ramp, slowed down to make the turn onto a residential street - then it happened again, just like the old carb had been doing when all this started - it bogged and died.

I dropped into neutral and it cranked right up; back into drive and made it a few hundred feet and slowed to cross a RR track; it bogged and died as I rolled over the tracks. Cranked right back up; made it a few blocks farther to my street; made the turn and it die rounding the corner. It started again and I made it into my driveway and killed it.

It fires right up and runs as long as I keep a little pressure on the accelerator. As soon as I let the rpm drop, it bogs and dies. This is the very same symptoms as the old carb exhibited, so I suspected this one may have dropped a main idle tube like the other had done. I pulled the carb apart and found both tubes intact, so that is not the problem this time.

Now, I am completely stumped!

Here is one observation that may mean something or not...
When I pulled to top off the carb, there wasn't any leakage at the seal between the carb halves. I was expecting the bowl to be full of fuel and it would pour out. When the top came off, there was only a tiny bit of fuel in the bowl. The floats were sitting on the floor of the bowl. If the bowl is full when the engine is running and the fuel pump is doing as it should be, and the needle valve is functioning properly, and the float height is set correctly, then where did the fuel go after the car sat overnight?

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

If the fuel bowl is empty after sitting, the fuel is either percolating (boiling) and siphoning into the intake manifold, which would tend to make the engine very hard to start (flooded), or it's draining and siphoning down thru leaky fuel pump valves, which would tend to make the engine hard to start (starved).

You may have water and/or crud built up in your fuel tank. Or you've got bad luck with carburetors.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dan, that's what is so odd. The car starts perfectly well. One press of the pedal sets the choke, one turn of the key and it fires right up.

I guess water or crud in the tank would be a cause for it to run badly, but that doesn't seem to be the problem. Once running at a higher rpm than idle, it runs fine. The main issue is at low rpm idle. That's why I suspected the main idle rod had fallen out like the other carb - not the case at all.

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

Try placing the end of a carb cleaner spray straw in the various air bleed holes visible as you peer down the carb, and blast them one at a time.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Got it running again. I don't know exactly what the problem was, but it's idling around 750 in PARK with 15-16 in Hg off the front of the carb.

I removed the carb, pulled the top off and blasted every orifice I could find with cleaner, confirmed the main idle tubes were intact in the venturi assembly, reset the float level (it was just a smidgen too high), reinstalled, and checked all screws and nuts for tightness.

After I got home Friday afternoon when the problem first developed, I sprayed the base of the carb with ether and noticed it affected the idle speed, like there was a vacuum leak. Maybe it was contributing to the problem. This time, I used some Form-a-Gasket between the intake surface and carb gasket to ensure a good seal.

I'll see how it goes in the morning...

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.