Technical Carburettor on Fiat Uno Cento 999c

[Lifesigns]

Hi there,

I am in a slight predicament and hope to find some help. I have a Uno Cento, stay in South Africa, and I am giving her a service before going away for a while. I have done almost everything on the vehicle myself and haven't had serious problems before, but this time I decided it was time to do the carburettor as I'm sure it's never been done. I bought a kit for it, Weber 32 TLF, and took the whole thing apart cleaning it etc. I then replaced all the old gaskets and stuff and upon replacing it found a problem. The car started for a few seconds put then died and when I had a look there was fuel all over the carb and surrounding area...

I had my girlfriend try and start it while I had a look but all that happened was fuel was bubbling from one of the copper type screws, the more she tried the more came out until it ran over. I have a Haynes manual but it doesn't have the Weber 32 TLF in it, so I am uncertain about calibrations. I'm sure I put it back together in the right way, I just think I have to set it now that it's clean.

Please if there is anyone with information on this Carburettor I would really appreciate it. I think it might be the float that isn't set correctly but it's the first time I've done a carb so I don't want to mess it up, hopefully I haven't already done that.

Thanks

 

[Chas Uno]

I think it might be the float that isn't set correctly but it's the first time I've done a carb so I don't want to mess it up, hopefully I haven't already done that.

Thanks

I'm 99% certain you haven't set the float height or needle valve correctly and are experiencing flooding. There might also be dirt on the needle valve that is stopping it from closing. What should happen is that the fuel enters the carburetor, the float chamber fills up with petrol, the float gets to a set height and then closes the needle valve that stops any more petrol from entering the carb. Once the fuel level goes down in the float bowl the needle valve opens again to allow more fuel in.

In your case the petrol isn't being shut off so the carburetor float bowl is overflowing causing the symptoms you describe. You need to take the carburetor apart again and reset the float height - detailed instructions should have been given with the carburetor overhaul kit. Failing that the Haynes Uno manual also gives details on how to set it.

The Weber 32 TLF carburetor is VERY simple. Just check that everything is correctly placed and tightened, make sure everything inside is spotlessly clean and check that the float height and needled valve are set and functioning correctly.

Good luck!

 

[Lifesigns]

Hey there,

I found it in the Haynes Manual and checked the float level. I set it very slightly and then put it back again. This time she started... and only after about ten seconds did the same happen. It wasn't as bad as before but it still came out. I'm somewhat perplexed by all this.

 

[Chas Uno]

Double check again. From memory you have to make sure that the float tab only just touches the needle valve at the correct setting. I think you have to hold the carburetor body sideways to do this? Also make sure the that needle valve itself isn't damaged. Did you replace it or use one that came with the kit? If it's the old one, look for signs of any ridges around the needle point, where it seats into the jet. If it is worn then it might not be seating properly hence not shutting off the fuel supply.

By the way, if the carburetor didn't flood before you overhauled it, then obviously it must be something you did to it! One option is to over compensate on the float height and deliberately make it too low. Then if it doesn't flood you know where the problem lies

 

[Lifesigns]

Hey there,

So I decided to give it a break for the latter part of yesterday and with "new" eyes I had a look this morning. Having had been the first time stripping a carburettor I checked were the new parts went as I removed the old ones. But the gasket for the fuel bowl was severely damaged and just broke to bits when I opened it so I couldn't see how it had been placed.

Only this morning did I find I had put it on the wrong half :idea: and although it sealed just fine a section of it was in the way and pushing down on the float assembly.

So after placing it beneath the float assembling and putting the carb back again I started her up and she was all smiles, along with me.

I'm still adjusting the carb a little as I'm not a hundred percent happy with the idling, but for the most part all is well.

Thanks for the advice.:worship:

 

[Chas Uno]

Result! :slayer:

 

[WEDGE1967]

hi you should take the carb off and check that the floats are closing the fuel of when the float chamber is full the simple way is to put a pipe on the fuel inlet and blow if the carb is upright the air will go through turn it upside down and you should find it difficalt to blow air through, if you can still blow air through try to bend the floats to put more pressure on the needle and seat (the small pin and seat under the float)
you could also try changing the needle and seat
p.s I live in Vanderbijlpark and drive a Uno cento 999cc, have done for a year now, would'nt trade it for anything

 

[yengulamit]

Guys i have 999 fire UNO(98 model.) As i m not too much aware about carb so wud like to knw which carbs were used in the Unos. The car has done 1lac+ kms on the odo. The engine has been pretty good, but off late its started missing. I checked all the spark plugs, the delco cover, motor etc. But lately found that the problem is with the carb.
I stay in Mumbai,India, so sourcing the parts for my baby is a problem.:bang: So what wud u guys suggest me. Should i get the carb petrol washed or change it altogether??