Yet Another Kadron Backfire Tread

[Heiferman]

I hate to post a new thread on this but it seems all these threads about Kads have different issues.

History - picked up a Thing with a 2180, a 120 cam and a 009 dizzy. Steel pushrods set at 0. Compression even across all cylinders.
The dual kadrons were just sitting on the manifolds and I had to replace the manifold studs.
I got them properly installed with all new gaskets.
I am running an electric fuel pump at just over 1.5psi.
The engine starts right up and runs at idle perfectly at 8 to 10 btdc at idle around 900 rpm on the 009. I balanced the carbs succesfully at idle with a snail. I timed it at 3000 rpm at about 30 btdc and have tried 26 to 32 always with similar results - random backfiring out of the one carb regardless of what side it is on.

One carb backfires out of the carb regardless of mixture setting on acceleration. One carb runs great and is begging me to tune it. I adjusted both accelerator pumps to about 8mm which was recomended elsewhere on the forum.

In order to evaluate the issue, I swapped the carbs side to side and have the same issue on the opposite side. Can't be manifolds at the head.

Suspecting a huge vacuum leak, I sprayed the outside with carb cleaner and got no throttle response.

I pulled the offending carb and replaced all the seals with a rebuild kit and sprayed carb cleaner through every orifice. Found no blockages. I reassemble and tried again. Same. Backfiring from one carb. I increased the mixture well past what I should suspecting a lean condition and it still happens and then I get black smoke from the exhaust (clearly too rich).

I did drive it with the backfire and it is acting like I have a huge vacuum.leak. Like HUGE! But the carb cleaner test gave me nothing.

Where am I at brains? I am at a loss.
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- 1973 Thing, some LandCruisers and an old Ambulance

[rayjay]

Gasket between the manifold and the head?

[Heiferman]

[Heiferman]

I tested for vacuum leaks with carb cleaner. I picked up some ether tonight and will try that tomorrow but I suspect I get nothing.
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- 1973 Thing, some LandCruisers and an old Ambulance

[rayjay]

Swap all the removable parts between the carbs. Jets, emulsion tubes, floats and float valves, accelerator pump bits.

[rayjay]

[Heiferman]

[thefinaldon]

Emulsion tube has come apart…

[Heiferman]

[quote="thefinaldon"]Emulsion tube has come apart…[/quote
How does that come out? Looks like it is tinned in.
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- 1973 Thing, some LandCruisers and an old Ambulance

[thefinaldon]

You need to pull this

Likely you will find this. I usually solder these up on Kadron rebuilds.

w

[thefinaldon]

Seems cavemanish…use a small screw ..thread it in and use vice grips to pull out.

[Heiferman]

[rayjay]

[Alstrup]

To me it sounds like the idle jets are different sizes
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[rayjay]

[Zed999]

[AlteWagen]

x2 on the emulsion tube. Sometimes water gets in there and clogs up the tube.

You didnt mention if they are solex or chinese clones. The clones are known to have issues and empi has stopped selling them until they figure it out.

EIS mixture screws are specific and cant be swapped with regular PICT screws.

When extracting the tube use a new drywall screw with the tip ground down so as to not affect the jet drilling.

Also run a small wire through all progression holes and the idle air bleed in the carb top and blow it all clear.

https://www.thesamba.com/vw/forum/viewtopic.php?t=...p;start=15
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Grapes of Wrath $200 Engine Rebuild
Official Dual Carb Thread
Cylinder Head Quick Reference Sheet

[Heiferman]

Well. That was not it.
I started with this since it seemed like an obvious issue.
Guess I will swap throttle bodies and see what happens.
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- 1973 Thing, some LandCruisers and an old Ambulance

[Dauz]

have you blown out the pilot jet with carb cleaner?

[Heiferman]