Help request for Weber 28/32 ADHA

[BobbyDee]

Hi all,
I just purchased a new spider. I’m in California and must pass the smog emissions test. I’ve searched online for information tutorials on how to rebuild the 28/32 but have had no luck. I aren’t worked with carbs before so if anyone can point me to good reference points I’d sure appreciate it. Or, are there other options to consider for CA emissions test.

[Nut124]

Did he car pass the test before? I would not rebuild the carb unless there is something wrong with the way it runs.

There are Fiat owners in CA at this forum. They will chime in I hope.

Replace the air cleaner element. Check ignition timing.

Without test results it's hard to know what to work on.

[18Fiatsandcounting]

As Nut stated above, it's hard to know where to start without knowing what part of the smog test is having issues. Visual inspection? CO emissions? NOx emissions? Hydrocarbons?

Some repair shops will run a smog check for you in an unofficial way. From there, you can see what the issues are.

Unfortunately, the '79 model year had the ADHA carb which was notorious for having issues. Common problems were loose vacuum hoses, or vacuum devices that have stopped working over the decades. But, I would check those before rebuilding the carburetor.

How does the engine run in general? How's the gas mileage? Exhaust look OK, without any blue or white or grey/black smoke?

-Bryan

[BobbyDee]

Yeah, I might be jumping the gun on the rebuild. I just bought it and wasn’t running. Got it to start and the carb is way too rich. Also, it’s been sitting for a few days and has a strong gas smell. I thought it might need new gaskets. It’s currently on a non ops in California. I’ll need to chase some things down for sure. Any good tutorials out there to help me along?

[PaulC]

I have a pdf of a rebuild i did for an ADHA on Mirafiori dot com if you're interested in a rebuild.

[BobbyDee]

PaulC, that would be a big help. I’ll see if I can find it. Thanks!

[18Fiatsandcounting]

Bobby, it's hard to know where to start with your car, but I'd suggest tracking down the "strong smell of gas" issue and the rich condition. Is the smell coming from the trunk or the engine compartment? Does it smell of gas when sitting, or only when running? Is the choke turning all the way off?

In general, if the fuel hoses are the original, the first step would likely be to replace those. All the ones in the trunk, as well as those leading to the carb. Any hoses or outlets that are open or appear to go to nowhere?

Lots of questions, but if you can post a few pictures of the engine compartment, maybe one of us can spot something amiss.

-Bryan

[wetminkey]

P.S. Most, but not all, of the 28/32 ADHA can be rebuilt. The main carb can be, but not all of the required diaphragms are available.
Rebuild and clean the carb body, and replace as many of the diaphragms as you can - that will be as much as you can do for your existing carb.
Be sure that all of your multi-colored vacuum hoses are attached properly, and not likely to leak,...and there are three thermocouples (mounted on the rear of the intake manifold) that must function properly. In addition, you've got a 'gulp valve' assembly on the drivers' inner fender that must work.
Perhaps you can begin to understand WHY the ADHA is kinda a "Lemon" carb system,...
PaulC and geospider know all about this! They can help a lot.
I swapped my '79 Spider to a single plane manifold and 32/36 DFEV because my car ran so poorly. I know you do not have that option, due to your location. I cleaned and rebuilt my ADHA, and then decided to 'park it' in a Weber box,...my entire ADHA system is boxed up. And I have all of my old system 'mapped out' (in case I, or someone else, needed to swap it back), so some of the info that I have may help you also. I've got some GREAT pics of the old system.
I'm easily contacted via Private Messaging on this forum, at any time.
Best of luck with your car!
Todd.

[geospider]

So, where in CA are you?

I have a '79 as well.
I run the stock set up for 1 day every 2 years. the rest of the time I run a 32/36 with the single plane manifold. much better and easier to use set up..
the stock set up is a PITA lots of vac lines that I doubt do much, although the secondary is Vac vs mechanical.
I have not had to rebuild the 28/32, but had a lo of help from a carb guru in the east bay area.. you do need this to pass CA smog. the visual part anyway. I can get the 32/36 to pass the sniffer part.

i would start with cleaning EVERYTHING and as Bryan had mentioned: chase down the fuel smell.
if crazy rich when running, check your oil; may smell like gas. the floats are very important to get right. I have learned not to trust any previous owner; unless from this forum of course.

Geo

[wubie317]

Bobby D...Just found this thread. I have a pdf of the weber 32ADFA manual with instructions on service etc. If you're interested, message me. I'm also in CA, so I feel your pain. BTW, I've passed smog every 2 years for the last 8 years, so know it's not that bad. Got a tip to put some extra octane in the tank and get the cat really, really hot just before going for the test. Worked for me most recently.