It makes sense. If a kaput capsule is leaning the mixture would that also account for the excessive midrange flat spot?

It seems the capsules are NLA as well. Do you just fit a blanking plate and make sure you don't use full choke or is there more to it than that?

Thanks for the replies everyone.

Jack

that will work, dont use the original screws as they foul the float if you dont shorten them

but is it fnackered?

Assuming it's just the diaphragm that's knackered, you can blank the airway off by removing the 4 screws holding the end on, and turning the end cover round by 90 degrees. It's what I've done with mine, took a matter of seconds, but of course it's still liable to fall off!

Without it, I tend to start my car on full choke, and then push the choke partway back in as soon as it fires.

An update.

The choke pull-off system is knackered - the diaphragm has several large splits in it. Whilst I was checking that I also checked the accelerator pump (which is fine) and the jets, which are (and were) clean.

This morning was pretty cold (a few degrees below freezing) and the 2CV wouldn't start. I could get it to splutter and occassionally fire but it wasn't having any of it. Judging from the smell there was plenty of fuel getting to the carb, in fact probably too much. In the end the battery began to die so I left it on charge and went to work in the Land Rover.

This evening (a few degs. warmer) the Citroen started eventually after a few splutters and lots of backfiring. For the first minute or so it would backfire every now and then and giving it any throttle made it hesitate, backfire a few times and then pick up. After a couple of minutes it was running and idling happily on a hint of choke.

The starting problem is obviously temperature related. It wouldn't start when it was below freezing today and was very difficult to start when it was just above freezing a week ago. With slightly higher temperatures it does the 'run, stop, start, run' thing.

So- would the kaput pull-off device cause this (excess air getting into the carb and counteracting the effect of the choke when cold????). I've ordered blanking plate and a service kit so if it doesn't work I'll have to start at first principles with plugs/points/condensor/tappets.

The one other thing that the internet has thrown up is the spacer between the carb and the manifolds. According to ECAS if this develops a crack or split you can get bad starting and backfiring, which would seem to fit. Is this worth checking if the other lines of enquiry don't work?

The irritating thing is the 2CV's running perfectly otherwise. I did 400+ miles in it at the weekend from Hampshire to Swansea and back and it didn't miss a beat.

Jack

i find my 2cv back fires in the cold, but only when the engine is cold, and normally its if i try to pull away after starting nearly straight away so load related!

Try the next things:

First, set the gap from the (new) spark plugs to 0,5mm. (normally around 0.7mm) the smaller the gap how easier a spark gets build, but to small and you don't ignite the petrol.

second. New points and condenser

third. put some new spark plug leads in.
Try to run the engine in complete darkness, maybee you can see some sparks comming from your leads probably going to the fenders or headlight bracket
then for sure you need new ones.

fourth: other coil

five;when it doesn't start by now sell it a.s.p.


a servised 2cv should start first try even with -15 degrees!!!

Don't stop the starter motor to early even when it starts to fire.....

you can crank for at least 10 or 15 seconds then wait 30 seconds and try again.

Before cranking, put the accelerator 2 or 3 times to full throttle and back
only with (very) cold engine.


When it didn't run for a month or more, keep pumping the accelerator during cranking.

Hi .....thats easily checked by squirting WD40 on it with the engine running .......even if the engine seems to be ticking over OK .....it will make some difference to the tickover speed if the spacer thingy is cracked.
btw .....you have checked that all four nuts are tight

best regards
T.

i found (for my car) fitting new ht leads caused a problem, my car never missed a beat in the rain, now with its new leads it does occasionally miss at speed, the leads i had on there where the originals, shouldnt of replaced them! oh well!

terry your right
the revs should rise? i learnt that trick when trying to work out why my old bike engine wouldnt run well!!