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Discussion Starter · #1 ·
My car's B18 has Weber 32/36 DGV (manual choke) that was installed by the PO. Car idles nicely when warm, but really poorly when cold - even with choke pulled out all the way it dies at full stops and occasionally backfires through the carburetor. I've posted this question also on the Brickboard and got some advice from Eric Hamlet regarding a modification to the linkage that can help fix the problem, but it seems bizarre that such a modification should be necessary. Just thought I'd see if anyone on here has experience with this carburetor and can offer suggestions.

The problem appears to stem from the fact that pulling the choke lever out all the way fails to completely close the butterflies; likewise pushing it in all the way does not completely open them. At either end - open or closed - the butterflies are still about five degrees or so off their completely closed/open settings. Partway closed doesn't seem to affect warm-engine operation, but partway open appears to be making the car run too lean when cold.

No amount of fiddling with the cable corrects the problem - no matter how it's adjusted the cable can't make the linkage travel far enough to close and open the butterflies completely. They can be closed and opened all the way manually.

Am I missing some adjustment that can help with this?

Thanks in advance for any suggestions.
 

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I haven't seen the problem of not enough cable travel to operate the choke butterfly completely. In fact, you should be able to have some fast idle function (the vertical S-shaped rod in the built-in linkage) left after the choke is pushed in far enough for the butterfly to open all the way. If you have the original choke control handle and the cable is hooked to the bell crank the handle operates, it should work. ???
 

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My car's B18 has Weber 32/36 DGV (manual choke) that was installed by the PO. Car idles nicely when warm, but really poorly when cold - even with choke pulled out all the way it dies at full stops and occasionally backfires through the carburetor. I've posted this question also on the Brickboard and got some advice from Eric Hamlet regarding a modification to the linkage that can help fix the problem, but it seems bizarre that such a modification should be necessary. Just thought I'd see if anyone on here has experience with this carburetor and can offer suggestions.

The problem appears to stem from the fact that pulling the choke lever out all the way fails to completely close the butterflies; likewise pushing it in all the way does not completely open them. At either end - open or closed - the butterflies are still about five degrees or so off their completely closed/open settings. Partway closed doesn't seem to affect warm-engine operation, but partway open appears to be making the car run too lean when cold.

No amount of fiddling with the cable corrects the problem - no matter how it's adjusted the cable can't make the linkage travel far enough to close and open the butterflies completely. They can be closed and opened all the way manually.

Am I missing some adjustment that can help with this?

Thanks in advance for any suggestions.
Assuming this is on your '68 Amazon and you are using the original choke cable/arrangement take a look under the dash where the cable makes a 180 at the attaching point for the choke handle. Note that the cable is actually a single wire with the ends originally operating the choke mechanisms on each dual carb. Currently, is the choke arrangement under the dash as original? Are both sheaths firmly anchored in the bracket so as not to move when the choke handle is operated?

Looking under the hood - where are those two ends in relation to the Weber and how are their sheaths anchored?

Any pics?

George Dill
 

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Discussion Starter · #4 ·
Sorry for the delay. I got distracted with a charging system upgrade.

A little further study and I realize that the butterfly appears to be operating correctly. I had thought that closing the butterfly completely would still allow enough air into the carburetor for it to run. Turns out that was wrong - closing it manually causes the engine to die. So it appears the butterfly is not the culprit.

More fooling around showed that even manually bumping up the idle speed, the engine still misfires occasionally, has *very* sluggish throttle response, and tends to stagger and die when cold. Are there any other adjustments on the Weber apart from the fast idle cam and choke butterflies that would affect cold operation?

Interestingly enough, there appears to be a very abrupt transition (in my engine, at least) between "cold" and "warm." The car will be running horribly, then all of a sudden everything will smooth out and purr.
 

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Discussion Starter · #5 ·
Assuming this is on your '68 Amazon and you are using the original choke cable/arrangement take a look under the dash where the cable makes a 180 at the attaching point for the choke handle. Note that the cable is actually a single wire with the ends originally operating the choke mechanisms on each dual carb. Currently, is the choke arrangement under the dash as original? Are both sheaths firmly anchored in the bracket so as not to move when the choke handle is operated?

Looking under the hood - where are those two ends in relation to the Weber and how are their sheaths anchored?

Any pics?

George Dill
George, it's a non-stock cable with a single wire. The wire appears to move properly when the choke handle is pulled.
 

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Phil, I think it's time to address how your DGV is jetted. There's an idle mixture screw, which is the horizontal one in the base of the carb. Warm up the engine fully, and then experiment with that to get the fastest/smoothest idle. If the idle speed increases, use the idle speed screw to bring it back down. It might take a pass or two going between those two adjustment.

Now turn off the engine, and turn the idle mixture screw all the way in until it seats using only light pressure. Count how many turns it takes to seat it, then turn it back out to its previous position (the engine won't run with it all the way seated). Ideally, it should take 1-1/2 turns. If it takes 2 turns, the primary idle jet is too small. If it takes less than 1-1/4 turns, that jet is too large.

Please report back...
 

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Discussion Starter · #9 ·
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