Right, maybe I should check out that jet then.

I'll see how it runs tomorrow. It's an absolute star normally and is still 100% reliable although getting quite hard to drive until warmed up, now.

How is the actual mixture adjusted then? Not that screw on the left with the offset slot on it? As far as I know that's just the idle mixture.

2cv carb problems , it’s a unusual unit having twin barrels , with lots of “ adjustments to play with ? , but a great piece of kit, imho ,
apart from the late version with the hidden primary jet

flooding from the top cover breather is usually down to a worn needle valve
(ECAS ) the top gasket is under no pressure , only gets damaged by clumsy handling ,float levels aren’t critical just stay close to the recommended , but floats rubbing/sticking against the chamber body is a sure sign of mishandling ,
the float arms are delicate , but re settable with light finger pressure ,

the idle/low speed jet look like it takes in air but it doesn’t , the 2 emulsion jets rarely get blocked ,

moving on to the heat shield spacer , that rarely fails unless the 4 carb/manifold nuts have been over tightened , that can bow the carburettor flange which just changing the gaskets wont cure , you need a good file and a surface plate (wink )

Don't use anything that could damage the inside surface of the jet. A cocktail stick is ok but I wouldn't use tweezers.
The difficulty is that once loosened, the jet usually stays in it's hole and there's nothing to get hold of to pull it out, hence the use of a cocktail stick.
What I do is take out the jet that is directly above the main jet and place a bit of tube over it's hole. Blowing into the tube will push the main jet out. (Put a finger over the blanking plug hole so the jet doesn't fly out through it). A drinking straw works fine or, (as I found out once at the roadside), a bit of windscreen washer hose.

Thanks. I guess I could check that 107 jet is securely screwed in? Otherwise I don't know, it's only been in a year or so.

The screws were loose on the top of the carb a little while ago which is when I first noticed fuel leaking. The fuel coming out was probably what spoiled the gasket on one side. I tightened them obviously which helped for a day or two but then it got much worse with the leaking.

Something working loose would make sense, what with the way it came on over a fairly short period of time.

Not a 2CV ....but I'm just saying because it's maybe worth checking...
I had a carb flooding problem on one of my motorcycles, no amount of "adjusting the float height" seemed to cure it, and tests with the needle vave showed that it was closing.
After about the sixth stripdown and float height adjustment [ all to no avail ] ..I took a magnifying glass to the alloy tab on the float which closes the needle valve [your 2CV floats has one of these].
Almost invisible to the naked eye was a small indentation which had worn into the alloy [it had worn because the brass needle in the valve was harder than the soft alloy tab] .....and looking at it magnified, it had worn like a bomb crater, with raised sides, the raised sides were stopping the needle seating properly .....five minutes spent filing & polishing the dent out .... with one of wifey's nail polishing files cured it.
hth
T.

Thanks Terry. Yeah I used that tab to adjust the float heights a little so it should be OK I think.

It's definitely running better than it was, I successfully transported my 96 year old friend to hospital and back. (2cvs are great for extremely elderly people, they're really easy to get in to!)

Still smoked on cold start and somewhat difficult while cold. OK once warmed up but hesitation is there & makes for a jerky drive really. Some puffs of smoke after hard throttle in 1st.

I'm thinking it's running rich. Tomorrow I'll take the top off again and check that primary jet is screwed in properly.

Ok, what colour Is this smoke?

Oh and I use plastic tweezers I've "borrowed) from my lab. More forceps I suppose.

The smoke is fairly light coloured. It's not burning oil I don't think, the plugs I took out yesterday looked good.

No more wet outside of carb so I'm guessing that was just the gasket. I fannied around a bit with that screw with the offset slot & in wondering if that helped a bit. Not sure though. (That one has a history of adjusting itself anyway.)

What's the fuel consumption like?

Is that the mixture screw?

The offset screw on the front of the carb is purely idle mixture - good for passing mot if turned in but bugger all difference when running under normal conditions - you can only really alter mixture by changing main jet in carburettor body.....