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Discussion Starter · #21 ·
definitly a slot where the blue arrow is
at the red arrow is a hole as it should be.

its not a DFAV . no diamonds or footballs

gone back to the first setting cause i had to make some miles on the autobahn

...........................primary..........................secondary
main:...................140............................135
air correction:.....165..............................165
idle:.........................55................................50
emulsion:.............. f50................................f6
Venturi:...................3,5...............................3,5


so driving on the autobahn gave me the opportunity to observe the problem precisely .
and its fascinating and confusing as well.
let me try to describe it in throttle opening stages:

idle area: throttle almost closed 13.8-14.2 (or what ever ).......... perfect
cruising area: throttle slightly open. lean condition........... not at all. it is rich @ 13.6 or so
light acceleration: throttle a bit more open. rich condition........... nope. i get values here that i wanted one stage earlier 15.5
but than.,when i open the throttle a bit more, way before the secondary opens......BAM!: rich condition as it should be! mid 13s

it looks almost, as if the cruising lean condition is a bit offset.

this is not an jetting issue, isn't it?
 

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Interesting, that definitely sounds modified. You should be okay on the idle speed screw @ 1.5 turns in from contact, I guess I’m kinda anal, I like to see the 0 vacuum reading at the ported connection on the carb.
If those progression holes have been opened up it would cause the rich condition at part throttle. Are you experiencing any flat spots during acceleration or light cruise?

The 32/36 Weber is designed to run lean during light acceleration to save fuel, you’re correct that usually happens when part throttle begins and you first crack those throttle plates open. Sounds like someone came up with a little too good of a remedy to cure the infamous off idle stumble.
 

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Discussion Starter · #23 ·
maybe tomorrow i have some time to check vacuum again.

at the moment it looks to me, as if i need another carb.

i have an old one which needs some rebuild at the throttle shaft
or i listen to opelbits and go to the 38...... but this one is not staged.......... hmm i love staged carbs
 

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Discussion Starter · #24 ·
Are you experiencing any flat spots during acceleration or light cruise?
actually not really. but i feel, that the engine is not as strong as it could be.
to be honest: there is a flat spot when i hit the pedal. u can see it in the display for a second that the afr is going way up .
the pumping system is not working very well. when i ran the engine for the first time some weeks back, it didn't worked at all.
i think the membrane is to stiff. it takes several seconds, after you fully moved it, to go back in normal position.
hope this will get more flexible at the time.
 

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As already mentioned, I would get a Spain made Weber 38 dges. They are great carburetors and will help give you stronger throttle response.
 

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None of the AFR readings are too far away from where they should be.

For the lean reading at light acceleration, then you need to change the spring or shorten the spring under the power valve. That enrichment that you see when you open the throttle a bit more is likely the power valve starting to open; it seems like you want it to open soooner. If you had a vacuum readings in the manifold, then you could be sure that is the issue.

You ought to be able to look down in the carb and move the throttle and see/hear the squirt of fuel if the acceleration pump is working.
 

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Discussion Starter · #29 ·
For the lean reading at light acceleration, then you need to change the spring or shorten the spring under the power valve. That enrichment that you see when you open the throttle a bit more is likely the power valve starting to open; it seems like you want it to open soooner. If you had a vacuum readings in the manifold, then you could be sure that is the issue.
makes sense to me. but how can i address the problem with to rich at cruise?
 

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I have no personal experience of FAJS carbs so I can't say anything about their quality. Some people seems to think they are ok, some say they suck. There is a thread at the moment on the German OHF. With that said, I have been contemplating converting an ohv manifold to fit a FAJS 44IDF and try the combination on a 12S.
 

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Discussion Starter · #32 ·
so i drank a couple of beers and thought about what Manta Rallier wrote.
my conclusion is: my vacuum is so high, that not only the carb misses the point when i'm in acceleration. but the exactly same happens with cruise (carb is still in idle mode).

is this an issue which an 38 could address, simply because its bigger?

i know what u are thinking...... get the f*** out and do some vacuum measurements! but i'm currently a bit restricted in my time and possibility's, because i'm currently on some kind of field service.
maybe tomorrow, but can't promise cause i'm not done with drinking yet
 

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Well finish the drinking first; that is important LOL.

I had not thought about the high vacuum from the larger displacement, but that might be a source of the variations from expected. The idle vacuum is certainly high. As for the rich at cruise, if the vacuum levels are high, then it may be sucking more fuel from the progressive slots than normal. If you put in a 1 step smaller idle jet, and re-adjusted the idle mixtrue, then you could see if that changed the overly rich cruise. If it did, then that would indicate the progressives are too 'active' at cruise. If not, then try a step smaller primary main jet instead.

For me, light to medium cruise vacuum levels normally show up in the 12-15 inches range. That's inches of mercury (in-Hg) which are the units we commonly use in North America. You would have to translate that to metric units over there.
 

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are they as good as original webers?
I have my eye on a 38/38 from Empi (same idea) for a third of the cost. For sale on EBay from a distributor in Florida. The one previously mentioned looks like a good 38/38 too. The good thing is that the jets from your 32/36 will work in the 38/38. I‘m jetted so I hit all the good AFR numbers on my 32/36 for the 2.0 that I own, I hardly ever have to use the secondary but it just feels like it Needs to breathe more.

The other possibility is that your 32/36 has a loose primary throttle shaft and the PO modified the progression circuit as a band aid. You should be able to diagnose that easily to check by trying to wobble the linkage, open & close the throttle plate while trying to wobble the ball stud. It might not show up with the throttle plates closed, it’s usually at its worst at tip in. If it’s loose then your 32/36 certainly isn’t worth putting any more time or money into.

If not, as MR said the AFR numbers you reported are right in there, over advanced ignition timing a possibility on the strong vacuum signal unless you already have that dialed in.
Some must have tools that have made things much easier for me:
1) Timing light with a dial, capable of reading the ignition timing at all engine speeds
2) Vacuum gauge
3) AFR gauge
4) Compression tester


I don’t really think you can go wrong buying the 38/38 wherever you decide to buy one, if you decide to. Keep up the good work and let us know where you end up next 🤙🏾
 

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Discussion Starter · #35 ·
If you put in a 1 step smaller idle jet, and re-adjusted the idle mixtrue
tried that. made no noticeable difference

throttle shaft is ok.
the ignition is currently 28° @ 3500 rpm w/o vacc

i'll hook the vacuum advance back to ported vacc, where it belongs. lets see if there is a difference .
 

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It sounds like you’re right on it.
I drove around with the vacuum advance to manifold for all the positive reasons that you read about but the engine seemed too have much advancement on higher rpm deceleration (throttle plates closed)with no backing off from the advancement, I just didn’t like that so I moved it back to the carburetor.
I’ve since tuned out the off idle stumbles, I found that getting the mixture screw to 1.5 turns out from bottom enriching my idle AFR to 12.5 or close took care of the little lean spot off idle. Back when I had trouble with that was another reason for trying the manifold vacuum advance.
All this discussion about vacuum advance, and I’m out of my depth here on the 2.4, I thought Opel did away with the vacuum advance in 75’ ? Or was that just on the FI 1.9’s?
 

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In the US maybe, but in Europe(except in Sweden with its own pollution control regulations) the vacuum advance was used on all L, LE-Jetronic equipped and carbureted models. The C24NE with Motronic had neither a vacuum or mechancal advance, the distributor was only used for distributing the spark, the ECU handled both the FI and spark timing.
 

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Discussion Starter · #39 ·
completely different question: at which AFR will the lubrication film be washed off from the cylinder walls?
 

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Good question... I'd expect that the problem is raw, liquid fuel getting on the cylinder walls. Once the engine is fully warmed, it is going to be hard/impossible to get the fuel vapor to condense back into droplets. Cold start enrichment is the most likely problem.

And, BTW, you are not going to see raw fuel droplets in the induction/exhaust registering on the AFR gauge. Since liquid fuel does not burn, it does not use oxygen, and so the droplets/liquid fuel can exist but the AFR will never see a change in the free oxygen content of the exhaust. So I am not sure you can truly give an AFR number for this problem.

The biggest issues I've experienced with lubrication washing off the cylinders has been with carb leaks dribbling raw fuel into the engine, both running and sitting. I had one inline 6 engine that the PO did not realize had a carb leak, and it took a .040" over bore to get cylinder #1 straight again.
 
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