Weber 32/36 DFEV Air Leak?

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Shadoobie
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Weber 32/36 DFEV Air Leak?

Post by Shadoobie » Wed Aug 08, 2018 9:03 pm

So I just got a Spanish Weber 32/36 DFEV from Carl and I'm having some trouble with it. The carb itself looks to be freshly rebuilt and in great shape, but I ran through every nook and cranny with carb cleaner and swapped the jets with some I know to be safe. Setting it at idle is a breeze, nothing unusual. However, as soon as I try to rev the engine around 1800rpm i hear a loud sucking noise and the car cuts out. Sometimes, if I hold the pedal to the floor, the secondary will carry it through to a higher rpm, but you can tell that the primary isn't doing anything. If I hold the choke closed over the at temp engine, though, it will lazily rev on the primary. I tore the carb completely down and cleaned out the Jets and everything else several times, but it doesn't seem to make any difference. I'm going to go ahead and strip it down again and soak it in chem dip overnight. Does anyone have any suggestions as to what else I should look at? -Josh
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bartigue
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Re: Weber 32/36 DFEV Air Leak?

Post by bartigue » Wed Aug 08, 2018 9:29 pm

Sounds like one or more progression holes are clogged, or the accelerator pump is not working. Or a few other things. You can soak the body and then blow it out with compressed air - remove the emulsion tubes and force air through there, noting if it comes out of the holes in the body.
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Brad Artigue
1982 Spider 2000
I've restored, worked on, sold, bartered, and bled for:
1970, 1979, 1980, 1981, 1982 124 Spiders -- 1969, 1970 850 Spiders -- 77 X1/9
http://fiat.artigue.com
Shadoobie
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Re: Weber 32/36 DFEV Air Leak?

Post by Shadoobie » Wed Aug 08, 2018 10:04 pm

The accelerator pump is definitely spraying, so I'm leaning towards a clog in the primary circuit somewhere. The carb was pretty clean in the bowl, but you know how that goes. Hopefully nothing a little bath in noxious chemicals can't cure.
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friedman
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Re: Weber 32/36 DFEV Air Leak?

Post by friedman » Thu Aug 09, 2018 9:36 am

First off, I will state I never used this carb so that takes me off the hook!

Seriously, you should post the jetting specs here so folks using this carb on their spiders can comment on that. I had an upgrade carb on one of my X1/9s that would idle fine but totally gasp and try to kill the motor whenever I gave it throttle input. Turns out the primary main jet was way way too lean and upjetting solved the problem.

The gasping could just be the sound of air being sucked into the venturis. Try using brake cleaner sprayed around the carb and the carb base to look for vacuum leaks, the revs should go up if there is a leak.
Carl in Virginia
80 spider
86 Bertone
77 X1/9
Shadoobie
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Re: Weber 32/36 DFEV Air Leak?

Post by Shadoobie » Thu Aug 09, 2018 1:42 pm

So I've let the carb body sit overnight in chem dip and rinsed it this morning, spraying it out with carb cleaner and then compressed air. I decided to swap jets and emulsion tubes with the old carb too. I could force air through both passages no problem. I assembled the carb and put it back on the car and nothing's changed.. So much for a quick fix. I certainly don't blame you Carl, the carb itself was extremely clean inside and out, and I've run worse without any problems. I was running this same carb before, so I know the jet size isn't the problem. I did swap jets with the old one just to be safe though.
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friedman
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Re: Weber 32/36 DFEV Air Leak?

Post by friedman » Fri Aug 10, 2018 9:05 am

Pull out the primary auxiliary venturi and make sure it's not in backwards. They can easily be installed backwards which will then block the fuel flow. They are spring loaded and you can either pull it out or gently tap it out from the underside.
Carl in Virginia
80 spider
86 Bertone
77 X1/9
Shadoobie
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Re: Weber 32/36 DFEV Air Leak?

Post by Shadoobie » Sat Aug 11, 2018 12:26 am

friedman wrote:
Fri Aug 10, 2018 9:05 am
Pull out the primary auxiliary venturi and make sure it's not in backwards. They can easily be installed backwards which will then block the fuel flow. They are spring loaded and you can either pull it out or gently tap it out from the underside.
You win the prize Carl. It appeared to be on correctly, but I swapped it with the venturi from the spare carb and now it runs like a champ! Thanks so much.
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friedman
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Re: Weber 32/36 DFEV Air Leak?

Post by friedman » Sat Aug 11, 2018 8:38 am

Never heard of a plugged aux. venturi but will add that to my list of things to check when rebuilding a carb. Glad it worked out.
Carl in Virginia
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bartigue
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Re: Weber 32/36 DFEV Air Leak?

Post by bartigue » Sun Aug 12, 2018 6:49 pm

friedman wrote:
Sat Aug 11, 2018 8:38 am
Never heard of a plugged aux. venturi but will add that to my list of things to check when rebuilding a carb. Glad it worked out.
They can be installed the wrong way and fuel won't flow through it at all.
-----------------------------------------------------------
Brad Artigue
1982 Spider 2000
I've restored, worked on, sold, bartered, and bled for:
1970, 1979, 1980, 1981, 1982 124 Spiders -- 1969, 1970 850 Spiders -- 77 X1/9
http://fiat.artigue.com
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friedman
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Re: Weber 32/36 DFEV Air Leak?

Post by friedman » Mon Aug 13, 2018 7:06 am

Brad, that was my suggestion earlier this month. Reversed venturi easy to do but a blocked one?
Carl in Virginia
80 spider
86 Bertone
77 X1/9
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