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Carb question: Do you think I have a good secondary ?


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Some background:

- 73 2002, basic stock carb, vacuum distributor.. 5 speed conversion !

- Already went to shop complaining about no secondary but they say it's fixed...

- I have no prior experience with 2002s but the car feels strong under 3500 rpm, but totally runs out of breath by 4000 rpm. You can reach 5/6000 in low gears "reasonably" fast, but by third gear, it feels pointless (too slow and labored, not much to be gained by staying in that gear)

Here's a picture of my carb: Is it me or does it look like 1/2 the carb is never used ? One side is shiny and clean, the other looks like a dusty dungeon...


The diaphragm at the carb was replaced (with a Mercedes part if I recall). The car DOES run OK and does reach higher RPM in low gears, but the best analogy I got is that it feels like a diesel (not a turbodiesel either - no like after 4000 RPM)

Can you describe in layman's terms what I should see to ensure the secondary does kick in ? Can I make it kick in sooner (force it)... Suck on a vacuum tube (where?), play with the gas pedal linkage to see something move ? (please be descriptive)

Am I better off going with a Weber conversion (without that effing system of vacuum?) Could I also replace the distributor with something not using vacuum while I'm at it ? (PS: if you said "yeah" on the weber, and feel so inclined, please supply a source for a ready to bolt on Weber for that car and I'll be eternally grateful)

I know, lots questions, but if I can't get this motor to rev better, I don't see the point of the car... It's not a ton of fun as is... I'm sure a 2.0 L should be more punchy above 4K rpm, I must be missing out... Please help, pictures or explanations for dummies welcome !


73 inka 2002 w/ fuel injection & 5 speed, LSD


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participated in the engine's operation for some time...it's dusty! Compare with the primary barrel which is nice and clean.

You can check on its operation by reving the engine quickly...work the accelerator linkage by hand with the air cleaner off. You should see the second barrel open.

I ditched the Solex on my '73 around 1979 or 80 primarily because the choke didn't operate properly, but IIRC that secondary opened with a bang at about 3500-4000 rpm. You could feel it as you accelerated.

If you paid money to have that secondary barrel made to work, they didn't do it. Take it back.

You might be able to remove the vacuum diaphragm and rig up a mechanical linkage for the second barrel, but finding a good used Weber is a lot easier. Lots of archive material on fitting a32/36 Weber and tuning it properly.



'69 Nevada sunroof-Wolfgang-bought new
'73 Sahara sunroof-Ludwig-since '78
'91 Brillantrot 318is sunroof-Georg Friederich 
Fiat Topolini (Benito & Luigi), Renault 4CVs (Anatole, Lucky Pierre, Brigette) & Kermit, the Bugeye Sprite

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agree with Mike - your dry secondary side hasn't worked

since Roy Rogers was on TV.

there is a diaphram in the round housing with "SOLEX" on the cover

and a M-B diaphramis ok, BUT there's either tiny rubber o-ring,

or paper gasket between the housing and carb body where it attaches.

Your leaking vacuum there and that's why no pull from the diaphram

to open the secondary.

That carb is nasty loking and needs a bath.

after you get the secondary vacuum diaphram/secondary

flap opening up - visit your carb throttle linkage to see if

your getting FULL OPENING( the throttle linkage is tapping

against the FULL OPEN stop on the side of the carb)

with the gas pedal at the carpet.

'86 R65 650cc #6128390 22,000m
'64 R27 250cc #383851 18,000m
'11 FORD Transit #T058971 28,000m "Truckette"
'13 500 ABARTH #DT600282 6,666m "TAZIO"

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I knew it.... I'm done with that shop....

Well, if I kinda liked the car with 1/2 a carb, I should really like it when it's fixed or replaced.

Could you humor me some more and recommend a place that sells a "bolt on" Weber (32/36 or 38/38 from what I read).... I googled it and it's an alphabet soup of designations... I'd like to find a place that sells them pre-jetted for my car so that I can avoid returning to my *previous* mechanic...

Thanks guys ! I'm really eager to feel the car run at full tilt !


73 inka 2002 w/ fuel injection & 5 speed, LSD


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forget the WEBER ! -

simply fix the carb you have already -

when working properly - you'll enjoy the car again.

Putting a new WEBER of unknown settings willnot make

your running problems go away. You still need

knowledge to adjust the WEBER. That same knowledge

needs to be directed to the SOLEX. That is less labor, less money.

less parts scrounging. Learn your SOLEX before jumping

into DEEPERWATERS. Your SOLEX will work when you

have a diagram of the correct parts, get your parts, and in the

end you'll say to everyone that THAT wasn't so hard.

And now I have original quality working better than ever.


tiny rubber o-ring might be missing = vacuum leak

the diaphram might be pinched from 'installation = vacuum leak

diaphram might be your OLD damaged diaphram (? ! )

is the diaphram lever even connected to the secondary flap ?

you asked how to test it = lift the diaphram lever up into the diaphram housing, and with free-finger

block off hole inside secondary throat to seal

vacuum into diaphram - with finger over secondary

hole, diaphram should hold up untill you remove

finger - then diaphram drops slowly.

Same thing with the diaphram housiing off the

carb - see that little inserted bushing with the tiny o-ring?

push diaphram up into housing, seal bushing with

finger = diaphram hold UP. Release finger = diaphram

drops slowly. If that inserted bushing is missing - fined the

hack you paid to fix this and shoot him dead with that

Giant's Football players gun - put gun back in dummy

footbal players hand, let him shoot his udder leg.

Enjoy your Secondary



the vacuum passage in the carb body going to

the tiny o-ring/inserted bushing (#'s 4 & 5 ) might be blocked?

with the secondary diaphram housing off - to the side-

spray carb cleaner into the carb body passage and

watch for exit down inside secondary throat. That

the hole you seal with your free finger when testing

the diaphram for holding vacuum. (-= WEAR EYE PROTECTION =- !!!)

'86 R65 650cc #6128390 22,000m
'64 R27 250cc #383851 18,000m
'11 FORD Transit #T058971 28,000m "Truckette"
'13 500 ABARTH #DT600282 6,666m "TAZIO"

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C.D. Is right, that vacuum box (round part that says solex) is not working. The rubber o ring is NLA, but you can get one close enough fit at local auto store, just get the assortment of o rings & use the smallest one. The o ring goes around a small brass orifice you'll see when you unscrew those 2 screws holding the vac box to the carb body. You can also smear a small amount of permatex ultra gray or similar gasket maker/sealant on the surface to seal it around the o ring etc.. just a real thin coat. If you find the vaccum box is shot, i.e. torn diaphragm inside it (your carb has 2 diaphragms), then a new one is about $90, and they are still available. Yes you can get a good used 32/36 weber for about $50 to $100 on ebay also, they don't use a vacuum box to open the secondary either.

2002 owner since 1980

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