Weber 38 DGES Tuning - JeepForum.com
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post #1 of 125 Old 05-07-2021, 09:44 AM Thread Starter
michael72
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Weber 38 DGES Tuning

Hello,

I am about to re-tune my carburetor and had one question.

In step #2, the choke is supposed to be warmed up and disengaged.

When I cycle the throttle linkage and it with a wood block and wedge to disengage the choke cam, do I leave the wedge in while I make my adjustments to hold the choke open?


Thank you,

Michael
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post #2 of 125 Old 05-07-2021, 09:53 AM
katwalk27
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Yes, the choke should be open. Warming it up should take care of that for you without needing a wooden block.
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post #3 of 125 Old 05-07-2021, 10:02 AM Thread Starter
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When she warms up, the choke is fully open.

The instructions say:

"All settings are done with choke disengaged and warmed up so that the choke is fully opened and disengaged. This is done on automatic carburetors (which I have) by first opening the choke butterfly by hand and inserting a wood block or wedge of some kind to hold open while the linkage is cycled (linkage operated through it's full movement) to clear the choke cam. (you will hear a metallic click as the choke cam is released. You can check the choke fast idle screw under the choke assembly to confirm that it is not in contact with the choke fast idle cam.)"

This tells me that the cam re-engages when the motor is turned off and needs to be disengaged before restart.

Am I correct?

Do I need it to stay wedged during the adjustments?

Thank you,

Michael

Last edited by michael72; 05-07-2021 at 10:03 AM. Reason: New content
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post #4 of 125 Old 05-07-2021, 10:18 AM
katwalk27
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If the motor is warm when you try to restart it, the choke should no re-engage itself. Is it an electric choke?
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post #5 of 125 Old 05-07-2021, 10:31 AM Thread Starter
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Yes, electric choke.

Thank you,

Michael
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post #6 of 125 Old 05-07-2021, 11:01 AM Thread Starter
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Good to go, left a message for Weber this morning and they just called back.

I do not need to leave the wedge in, I just need to hold the choke plates open while I cycle the linkage to disengage the choke cam once, he suggested that a finger would work just as well.

Thank you for your help katwalk27.

Thank you,

Michael
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post #7 of 125 Old 05-07-2021, 01:49 PM
katwalk27
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no problem
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post #8 of 125 Old 05-07-2021, 08:59 PM
JEEPFELLER
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katwalk27

I'm not a big WEB fan

Yes he has a 'lectric choke

Explain to him how and to see if the 'lectric part is a doin' what it's supposed to do

Just cause it's electric does not mean it works---or might be hooked up wrong.

On top of all of that, the mechanical adjustments it needs before the power kicks in.

michael72 has a nice Jeep, I could help him out if he still had the BBD or even a nice Holley

Post 8 on here https://www.jeepforum.com/forum/f8/w...quest-4425199/

Don't even suggest a "38" unless you are you better than a 20 year veteran Weber tech? If you go to Amazon put in your CJ info, you will still find they want you to have a 32/36! With the same promises I got in 2000.

This is why I can't tune one, it's impossible to make one do what they say it should do.

Here we go, 20 years later, the same write up as before, no "Updates"?

https://www.morris4x4center.com/webe...SABEgLuRPD_BwE

So please "Kindergarten" Micheal72 thru the best it can be adjusted, or tell him he needs to invest in a real carburetor.

I messed with mine for a few years, 'reckon with what little his has been used they might refund his money?

What I mean here is don't string him along with bad info (or not) he's too nice of a guy to have a crappy running Jeep.

---JEEPFELLER
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good one.jpg  
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post #9 of 125 Old 05-08-2021, 06:58 AM
John Strenk
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He already has the 38DGAS.
Webers are fine carburettors and there is exhaustive research on this forum on how to make a 38 work.
You really don't need to be a 20 year veteran to make a 38 work. Plenty of Weber veterans on this form to to explain it Barney style.

I agree, The 32/36 is a terrible carb for a 4.2. best used on a 1.3 Fiat 128.

If you are really looking for some self inflicted misery try tuning a Hitachi carb on a Sammi
I put a FrankenWeber (top of a Holley/Weber off a Pinto and bottom off a pure Weber) on mine with an Isky cam and headers and it passed emission and never missed a beat for the next 4 years I owned it.
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I drive a Prius to save money and buy more Jeep Parts....
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post #10 of 125 Old 05-08-2021, 10:28 AM
torkman1983
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I replaced the 36 with a 38 and with help on this forum tuned it up in about 30 minutes. Jeep runs great, idles perfect, no hesitation, strong acceleration. So my experience with the 38 was great and I had no issues getting a good tune out of it by following the tuning directions closely. Very glad I made the upgrade.
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post #11 of 125 Old 05-09-2021, 11:30 AM Thread Starter
michael72
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Hello,

I am down to the carburetor for sure now.

She is pumping too much fuel.

Hard start and no restart when warm.

When I opened the throttle plates after she would not restart, there was raw fuel in the bottom of the intake and heavy fuel vapor. The choke was fully open and the choke circuit is working.

I am learning the terminology but I think that I am experiencing flooding and vapor lock.

When she was running with the choke warmed up at idle it sounded like there was some spitting going on in the carburetor throat instead of a constant sound. That sounds like an obstruction to me.

If the carburetor is messed up, I have a few thoughts about what caused it:

1. Sat for 9 months on the shelf with residual gas in it.

2. Bounced around on the shelf: I noticed that my electric choke had rotated on its own. I have included a picture
of what it looked like after I installed it two years ago, what it looked like on Friday, and what it looked like after
I adjusted it. After I noticed this, I adjusted the choke (while cold in the morning) so that the plates just
touched the carburetor. The silver ring will not go back to the original orientation.

3. An oil overfill called for a new PCV valve: Some oil got into the carburetor and caused some damage.

4. I have set the lean best idle about 10 times by now and I may have damaged the seats even though I made
sure not to bind the screws. When I use a vacuum gauge, adjusting the idle mixture screws dose not make any
changes. This concerns me the most because I do not know if
that damage is permanent.

I am willing to rebuild and would like some advice before I pull it off.

Would any of the issues above indicate the need for a rebuild and could issue #4 be the end of my carburetor?

If I have to rebuild, while wading through the carburetor wars, I saw that people did all sorts things when it came to changing jets and other things. I figured it would be a neat thing to do in the future. If the future is now, any modification suggestions would be welcome.

I am going to have to become a little more familiar with the terminology and possibly tools for this. I have experience rebuilding carburetors but those were for lawnmowers, snow blowers, and one for an old Honda motorcycle for my friend. None of these really had any specifications to follow. Took them apart, cleaned them, new gaskets, back together.

My instinct is that you guys are going to zero in on my choke and find the problem.

Timing good and no vacuum leaks.

Thanks guys.
Attached Thumbnails
Choke 1.jpg   Choke 2.jpg   Choke 3.jpg  

Thank you,

Michael

Last edited by michael72; 05-09-2021 at 11:34 AM. Reason: Format
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post #12 of 125 Old 05-09-2021, 02:03 PM Thread Starter
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I did this incorrectly on Friday:

https://itstillruns.com/adjust-weber...e-7925420.html

This will be the first thing that I do when I get back to it.

If someone could point me to some good resources for tuning, I would appreciate it.

Thank you,

Michael
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post #13 of 125 Old 05-09-2021, 07:26 PM
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Ok, so more back history tells me that this carb needs a rebuild, a clean and a check of float levels. It may have had oil in it and has been sitting for some months with old fuel init, which dries out to a white powder that clogs up all sorts of areas. Whilst not a particularly sensitive carb it would benefit from a strip and clean.

What fuel pump are you using and are you using the 3 way filter with the tank return? I am just asking to get a idea f what inlet fuel pressure your inlet valve is coping with. The stock inlet valve is quite good out of the box, there is a viton upgrade that can handle more, and a rebuild kit would come with a new one.
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1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
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post #14 of 125 Old 05-09-2021, 07:44 PM
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Pretty much rule out "Vapor Lock"

You fuel lines are not being excessively heated by the exhaust/ exhaust manifold

The "3" port fuel filter keeps fuel moving (from the tank and back through the return

With the fuel moving, It is doubtful It the it could sit still and get hot enough to turn into vapor.

Y'all WEBER Guys need to jump in!

It cranks, it runs. (not sure what it takes to get it running)

Shut it off----it will not restart?

That's what ya'll need to address.

----JEEPFELLER
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post #15 of 125 Old 05-10-2021, 10:35 PM
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FWIW, While out and about in my Jeep last year (with a year old reman Carter BBD), decided it no longer wanted to start unless I pushed it down a hill and popped the clutch.

Thinking it was the carb, I ordered and installed a brand new Weber 38. I initially experienced the same problem you describe. I called Tom @ Redline Weber and he helped me through the process. Through his guidance I ultimately found serious corrosion in the ignition module connectors.

I swapped in an HEI dizzy and got it up running.

I need to get back at it as it can be hard to start after sitting a few days. But I am confident that is just a matter of fine tuning it.

Good luck!

1983 CJ7, 258 engine, T-4 trans. Mostly stock with some useful upgrades.
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