new Kadrons sputtering on low RPM

[Holzy22]

Just installed a brand new 1915 motor into my bus. Had it running pretty good with the original dual 32 PDIST set up. Decided to buy the 40k 40mm Kadron dual carb kit.
It idles fine and cruises at high RPM just fine, but on initial take off, or after switching gears and the rpms drop, it sputters and stalls then sort of catches (if that make sense) and then goes great. Then I change gears or slow down and it sputters again until higher RPMS are achieved.

I have:
Perfect balance on both carbs,
3/8 line from manifold to manifold to balance.
Enrichment on both dialed in.
timing is at 10 static and 30 total.
bosch SVDA distributor hooked up to the right carb.


thoughts?

[APPLEGREENVW]

Put the 32 PDIST back on, and forget about the EMPI 40K carbs.
I didn't have luck with them either.
https://www.thesamba.com/vw/forum/viewtopic.php?t=726382&highlight=40k
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02/76 Beetle sedan

[Holzy22]

Nooooo, don't tell me that, just spent $750 on them cause I thought my new 1915 needed more than those 32's.

Have to get them to work.

My brake booster is also T'd off from the balance line, could that be playing havoc with the set up?

[APPLEGREENVW]

[Alstrup]

[richparker]

Kaddies weren’t so good for me. IDFs have been very good tho. Both Webers and Chinese knock offs have been excellent.
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[Chuey]

You sure got a lot of negative responses. Without calling anyone wrong, I would keep in mind that more than a few people have successfully used those carbs and they have a good reputation, overall.
My personal experience with them was wonderful with years of un- temperamental smooth reliability. I have a set waiting for the engine I’m gathering parts for.
With your symptoms, I would wonder if the fuel pressure is higher than recommended. Do you have a fuel pressure regulator?
I would wait until someone who understands Kadrons chimes in. Kaddy Shack is an obvious resource.

Chuey

[APPLEGREENVW]

[Holzy22]

Yes, doesn't seem to be much love for these, but I have them now and am determined to make them work. CIP said these ones would be the most fool proof with almost no issues.

The engine is a pretty stock 1915. Stock cam and heads as far as performance upgrades.

It feels like the carbs are starving for fuel for that brief moment, that's my guess. I will get a fuel pressure reg on there, but never had an issue before. Maybe not enough pressure to deliver enough fuel? I have not touched the pumps, they are adjusted the same as they came. Will call empi after the holidays to check on that.

[Rome]

About 25 yrs ago I had a similar issue with genuine Kads on my nearly stock 1600 in my '77 Beetle. Hesitation when starting off. I tried these instructions to adjust the accelerator pump, which improved and nearly eliminated the hesitation. http://www.lowbugget.com/main_page.html Also aimed the accel pump squirt tube slightly so that the fuel stream aimed right at the gap of the throttle plate and the carb inside wall when the throttle started to open.

The Beetle has utilized a low-pressure Facet-style electric fuel pump from the PO for numerous types of carbs, from Dell'Orto dual throats, Weber IDFs, Kads, and most recently even a stock Solex single. Fuel line pressure using a test gauge is about 2.5 psi.

[Alstrup]

[Holzy22]

wow, really, need to do all of that just to make these carbs work. As per a previous post, should I just put my 32 PDIST's back on? Is there a big performance difference even if I get these K's to work? Assumed a 1915 needed bigger carbs.

[APPLEGREENVW]

[Alstrup]

Well, yes, and no. It not like the 32´s will solve your problems. The 32´s are simply masking your issues with limiting the airflow to the engine. If you built the engine like I assumed and laid out above you will not feel the difference between a less than good timing setting versus an optimum, because the engine can´t breathe enough for it to make a difference.
In a well tuned set up the power difference between the 32´s and the Kads will be somewhere between 7 & 10 hp
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[Holzy22]

lol I didn't know I had problems, but I get what you are saying, performance from my new 1915 may have been limited by the 32's and to get it to breathe fully, the 40ks, tuned properly with the engine will do that. And yes that's what I am looking for. So I am going to forge on and and get them dialed in.

[craigman]

My local vw shop sent 3 sets of EMPI Kids back to EMPI to try and figure out why they don't work. Until further notice, they're not selling any more EMPI kads.

[Holzy22]

Tuned them a little more as per Alstrup. Gave the pumps 1 turn, adjusted the idle mixture screws one more time. Did not increase the jets...yet. Road test was better, still a little hesitation when shifting gears, but better. But you can tell they just feel a little off. Will talk with EMPI and Kris at CIP Canada, (he is awesome), and see what they recommend as well.

[Alstrup]

Empi will just give you a story from Africa. CIP I do not know.
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[Holzy22]

Was just thinking, actually the oil that flung onto my new right side air filter (uuugh) got me thinking, I have not set up the PCV valve venting yet. My breather tube is just wide open for now. Would this make a difference? I cant see PCV pressure in the motor causing any of my sputtering issues, but it did get me going down an internet rabbit hole on PCV venting.

[67rustavenger]

Is this not your current engine filtration and case vapor ventilation system?

If so, are you running the oil vapor recovery system from the breather/oil filler tower like in the image above?

If not, adapt your breather tube to one of you intake filters, or a breather box of some sort.
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