Weber Jets

[Nanonevol]

So I purchase a 34ADF from a forum member and already lost one of the main jets! Where do we get these and which one should I get for my stock 1977? The remaining one is a 159.
Also, I read elsewhere of 2 idle jets values for this carb. Is not the idle jet the horizontal screw with the tiny perpendicular hole, which is marked 80 on mine? Is there another?

[So Cal Mark]

I have a pretty good selection of jets. There is a low speed jet in the secondary. For the main jet, you don't mention whether it's a primary or secondary. The sizes will vary depending which one you need

[Nanonevol]

Thank you Mark. Hopefully Allisons can help. I'm fascinated with this Weber and have so many questions. Calling all carb gurus!
The 159 is the primary main and I'm missing the secondary. I've read recommended here to be 120/140 so I may need both? Also, I'm curious about my emulsion tubes but I don't see how to get them out of these holes here under my air jets.
And is this an idle jet stamped "80"? edit -yes

And this is...? edit - idle mixture screw

[zachmac]

Exploded diagram can be found here: http://www.piercemanifolds.com/category_s/229.html These guys are also a great source of parts and info for Webers.

You should also buy and read this book: http://www.amazon.com/Weber-Carburetors ... carburetor

[Nanonevol]

Thanks, that book looks good. I did get a different book on Webers by John Passini, but it never mentions the ADF's and is a difficult read. I guess I'll get jets from Pierce Manifolds. Still would like to look at those emulsion tubes but not trying to mangle up anything.

[Nanonevol]

Still have questions if there's any carb folk out there. This photo shows my air jets.
Isn't my primary on the right with the accelerator pump facing into it? Then aren't my air jets reversed here, in other words the 145 should be on the right/primary and the 180 on the left/secondary? I did manage to get the emulsion tubes out and I think they may be reversed also - I have a f5 on the left/secondary and an f20 on the right/primary? Are these not reversed as well? I suppose I can ask Pierce manifolds but I thought I'd try here first.

[Nanonevol]

I think I'm not getting much informative response here because no one knows. It's not my breath... So I've read every relevant post I can find on this forum and others and I think I'll be alright with what I have which is:

Idle 55/80
Main 120/140 (purchased after one of them went into orbit while being Dremeled)
Air 180/145
Emulsion f20/f5
Acc pump is 45

Someone suggested I time the car from 40 to 60 mph with the 32ADF and then when I put the 34 on.

[aj81spider]

Here's the Fiat specs for jetting on the carburetors by year. Yours wasn't a stock carb, but the jetting on the 32 might be useful.

[Nanonevol]

Thanks, hadn't seen that one actually.

[131]

34ADFA 50 was fitted to 2 litre 131s in Oz.

Main venturi. 24, 26
Main jet. 120 +/- 0.05mm, 125 +/- 0.05mm
Air corrector jet. 190 +/- 0.10mm, 165 +/- 0.10mm
Emulsion tube. F84, F5
Idle jet. 50, 90
Air idle jet. 80, 70
Accelerator pump jet. 0.45mm

[Nanonevol]

Finally had an afternoon to install the 34ADF. Car starts and idles fine but only accelerates gradually. If I step on the gas, the car stumbles. I used the following jetting:
Primary/Secondary
Idle 55/80
Main 120/140
Air 180/145
Emulsion f20/f5
Acc. pump is 45
I don't have a clue how to remedy this.

[131]

Check the accelerator pump diaphragm. When opening the throttle there should be a good squirt out of the pump jet. There is a measurement for volume, 6ccs for 10 pumps or something, I've never measured it.

[Nanonevol]

Thanks, I'll look at it. The accelerator pump diaphragm is new. I have to trouble shoot this starting with the basics. It may be a vacuum leak. It may be a clogged fuel filter. It may be the mixture setting. Took a spin yesterday after plugging now unused vacuum line but the car still bogs and hesitates and once even acted like it was running out of gas. Thought I might be stranded but then the motor recovered. I'll get some new plugs so I can analyze.

[Nanonevol]

Well the car is running much better now with the 34ADF. Starts easily (that's new), doesn't stall sometimes when coming to a stop (that's new) and idles around 900 smoothly (that's new). There is some hesitation, though through the whole range I believe and that's new too. Acceleration is smooth but occurs slowly. I don't have a clue what to do about it. I don't think it's me asking to much of the car, it was quicker with the 32ADF.

[Nanonevol]

So I theorized that since the car ran fairly well the 32ADF jetting, I'd try those in the 34ADF and see if I could improve the stumbling acceleration. I'm starting with the easy ones of course, the air jets and emulsion tubes since I can do those without any other disassembly. The result was that the stumbling moved from the 2000 and up rpm area to stumbling at takeoff and wasn't too bad at speed. So I swapped them back again and just for the heck of it tried putting the F73 emulsion tube that was in the 32's primary in my 34 secondary and voila! I won't say it's perfect but it's fairly ok judging from a short ride. I suppose I'll try some more jet fiddling, say with the main jets and maybe try the 50 accelerator pump from the 32 but is this how it's done?
From what I've read the selection of these various emulsion tubes is a bit mysterious. For the record, here's what I've got:
Idle: 55/80
Main: 120/140
Air: 180/170
Accel pump 45
emulsion tubes F20/F73
Any feedback from those more experienced is appreciated.
By the way, I'm wondering how this 34ADF carb is supposed to give such a great improvement over the 32ADF as they look quite similar to me except that the 34's venturis are a silly millimeter larger at 24 and 26.