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Zenith 28IF problem solving

Hi,

I've have had all kind of funny stuff with my 28IF.
Last summer i succeeded to buy old stock of sealing set(photo enclosed), unused parts from 1971 !!
Even the mix screw which must be almost impossible to find(paid 1Euro), butterfly flap shaft sealing(small white look like a stefa sealing), old shaft sealing was of rubber(original from -76/77) but this earlier was f plastics. And guess what, a suction manifold original sealing from -71-i guess it must contain asbestos !

20201008_173151 (3).jpg
 
Thank you for all the Zenith 28 info. I know everyone likes to hear a happy ending, and I'm pleased to say that with a good clean and a new gasket (warmed and mixture screw fiddled with), the engine runs and ticks over beautifully.

I've seen a lot of talk of the 1.3mm bore restrictor in the plastic T off the carb. I can't see a restrictor in mine. If it's in the hose on the manifold side it must be very well hidden. Does anyone with restrictor in place know where this ought to be please? I saw the useful post of how to fashion one of these (from a bolt and drill it out), but I just wanted to check if I ought to be able to see it.

Thank you,

Ben
 
Thank you Andy. Very useful and much appreciated. I found mine half way along that bit of tube, and gunked up to the point that I couldn't blow air from one end to the next. Now clean as a whistle and even though I thought the carb was better for a clean, there's a crispness (possibly imagined) now which I suggest may be for improved breathing through the manifold tube/ restrictor.

The car now pulls and revs very nicely. There's still an occasional stutter when rolling back onto the throttle (usually out of a corner) in third and fourth. It seems like a momentary misfire (enough to give the engine/ drivetrain an unpleasant clonk/ shudder). Trying to imagine what this might be: The carb is clean, and has new fuel. I didn't replace the diaphragm (having ordered the wrong kit from Franzose), but I wonder if this could be the culprit (it was in one piece, if a little floppy). The fact that it's on an opening throttle makes me wonder what level of throttle opening that pump/ diaphragm might influence. I'd imagined most effect when giving it a significant boot of throttle, not the gentle rolling on that it occurs at. Possibly electrical? Any thoughts very welcome.

All the best, Ben
 
You have the Spanish 28IF with accelerator pump, that's what this diaphragm is. If it's stiff it will not be able to squirt any fuel through the discharge jet, and you will get exactly this stumble. Can you post a photo of it with dimensions? I may be able to help, I have lots of diaphragms but don't have such a carb in my hands to check if any of them fits.
 
Thanks for the response Angel. The diaphragm I need is http://www.franzose.de/en/Renault/Alle/Vergaser-Vergaserdichtsaetze/ANR82862/ and I'm happy to buy it. I just wanted to check with the forum if it seemed a likely cause of my stutter/ stumble when opening the throttle before ordering it. Your experience makes me think it's worth trying, thank you. I'll order one tomorrow.

I mentioned in the thread above, but if anyone would like the diaphragm from the kit I incorrectly bought http://www.franzose.de/en/Renault/Alle/Vergaser-Vergaserdichtsaetze/ANR82872/ they are very welcome to it free of charge.
 
Cabled Choke closing on it's own... reason, solution? tnx...
p.s. carb is overhauled.. the cable was torn off so I merge it with epoxy metal..

carburatore lavato.JPG
 
@Andy McGhee , no, I have it ... but I can't use it anymore because there's no cable sleeve in that part of the choke... due to "welding"..

choke cable welding.JPG
 
Hello everyone,
I'll be gratefull if someone could help me to find the correct kit for my 28IF carburetor. There is a code on the side V.05075A which I guess is the "version". does anyone know which kit code should I search for? Someone told me the "S25F.1F" code is the correct one for my carburetor kit, but I would have another opinion.

Thanks
 
pumiddu said:
Hello everyone,
I'll be gratefull if someone could help me to find the correct kit for my 28IF carburetor. There is a code on the side V.05075A which I guess is the "version". does anyone know which kit code should I search for? Someone told me the "S25F.1F" code is the correct one for my carburetor kit, but I would have another opinion.

Thanks
Click to expand...
I've used Meat and Doria kits before - S25F was the part number (slightly different to the kit you mention). As you're in Italy, it'd be easy enough to get in touch with them to check!

Part Number S25F | Meat&Doria

www.meat-doria.com www.meat-doria.com

Azienda | Meat&Doria

www.meat-doria.com www.meat-doria.com
 
Whole set of internal parts for Zenith 28 IF is available on AliExpress.
This is what you get inside.
IMG_20240329_184842.jpg

Even whole carb is available but do not know quality of it.

Think that JonathanT have one reproduction zeniths on his car

Maybe @JonathanT can say few words how that reproduction Zenith 28IF works

​

 
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