funny hoses and carb settings

[Johannes]

Hello Folks,

I want to understand how my carb works because I have stuttering in acceleration when I press the gas pedal about 2/3. I have done a lot of reading (also in this great forum) but now I am stuck.
When I press the pedal for 1/3 I have no troubles and when I hit full throttle I also have no troubles. Stuttering only occurs at 2/3 of gas pedal way.

Here are the facts about my car:

1978 CS1 1756ccm, probably California car now in Austria
Motor number: 132A1.03.6 (I found out it is a California motor)
Head number: 134AS.6C
Carb: 34 DMTR 51/250 8J

I have a few hoses dangling around which are blocked/closed with a screw. I think they are left from the original carb or the smog stuff, I want to find out with your help. Maybe there is an issue.


These two hoses coming out of the intake manifold, 1 is connected to the barrel 1 of the carb, and the second one is blocked. In the carb barrel 2 is also a blocked hose – should they two be connected? I don´t want to try things I don´t understand.


What are these hoses on the intake manifold?
The red one is blocked. And also the green one. From the blue one is only one side blocked.
Can you explain this to me?

I want to block the holes professionally.
Do you have any idea how I can adjust my carb to work correct?

Thanks in advance,
Johannes

[SteinOnkel]

Hallo Hannes,

Okay, I did this last year on my car when I went to a non-smog carburetor. Which is what you now have. That's why you have so many extra hoses left over.

Basically, it boils down to this. Everything on connected to the carburetor runs off of a vacuum signal. There are two types of signal. Ported and non-ported. Some carburetors have only one, others both. To determine what you have, stick a hose onto the carb port in question, start the engine and put your finger over the open end of the hose. You feel a pulse at idle and if you rev the engine? Great, that's non-ported. Only at idle? That's ported.

You now only have two components really on your car that need a vacuum signal. One is for the brake booster, this one is not optional. It will need non-ported vacuum from a large diamter source (i.e. not your carb). Second picture blue circle, one of those hoses will go the booster.

Second component is the distributor. They are factory hooked up to ported vacuum, but most aftermarket carbs don't have a ported vacuum. That's okay. You can hook up the dizzy to a ported vacuum signal, no problem. It only advances the ignition timing under high vac/low load scenarios i.e. cruising on the Autobahn. It is for fuel economy and therefore optional. However, even here in California with crappy pump gasoline, I have never had the engine detonate or ping with the vac advance connected to a non-ported vacuum signal. You will for sure not have an issue in Europe, where gasoline is of much higher quality and octane.

And that's it. You can remove, plug and bin everything else. Fiat used a bunch of different threads (some of them special and hard to find) so what I did was take the ports out of the manifold, clamp them down in a vice and then weld them shut.

[davidbruce]

Hi Johannes. As near as I can tell your carb was never installed on a 124 from the factory. So who knows how or what it was jetted for. Before doing any adjustments I would first double and triple check that you have no vacuum leaks. I would then check that the ignition system is set to specs and working properly. Is the distributor vacuum advance hooked up and working properly. No leaks in the vacuum diaphragm. Is the float level and float drop set to specs. Is there any debris in the float bowl. After answering yes to all of these questions use this link to adjust and troubleshoot it.
https://www.carburetion.com/Weber/adjust.htm

As far as blocking off the ports and hoses. You can get vacuum caps in various sizes at auto parts stores or Amazon. I went to a hydraulic shop that specialized in hose and fittings and was able to find the proper size plugs for the fittings that go nowhere.

[Johannes]

Also here many thanks for your help!
I will try your input in a few days when I am back at the car.
Yes, you are right Dave, it is not original and I have the info that it was a common conversion kit for spiders years ago in Germany. There came a paper with it, but I don`t understand it yet really.

For my understanding:
1. The non-ported vacuum comes from the intake manifold? (because of the pistons moving down I suppose)
2. Where does ported vacuum come from?
3. How do I check the vac hoses, looking at them or wiggling when the engine is running?
4. Steiny what do you mean with pulse? Is it a pressure or a vacuum? Do I have to block the hose which is going to the intake manifold?
5. Could it be that my distributor don´t have a vacuum hose? I am not near the car at the moment so I can´t have a look, but at the picture I took last time I can´t see a hose.
But when there is a hose where should it be connected, to the intake manifold or somewhere on the carb?
6. For what is the green plug on the 2. picture, can I remove it for a professional plug?
7. Where should I mount the hose from the distributor?
8. Could it be that my acceleration pump is defect because of the stuttering at 2/3 gas pedal?

Yes, the blue hose is going to the brake booster.

Sorry for my stupid questions, I am at the beginning of understanding the old technology. I have only worked on single cylinder motorbikes with easy carbs.
I can´t find a manual for this carb where it is explained how the hoses should be connected..

Hannes

[Johannes]

I think a have missing parts on my carb. What is this thing and is it important?
I think the green hose should be connected to it, it has something to do with the choke.