The Solex 23/36 CISC carburettor was fitted to the 2CV, Dyane, Visa and LN(A). Leaving aside the 652cc engines, there were two models fitted to the 602cc engines and they differ in the sizes of the chokes.
Information on these in the Citroën workshop manuals is contained in a few cross referenced tables which are just about intelligible if you are looking for information on a specific car but make it very hard to come up with a simple guide. Not that I’m going to let that stop me – here’s my working overview of the main types of 23/36 carbs.
First choke venturi [mm] (area [mm^2])
Second choke venturi [mm] (area [mm^2])
First choke main jet
Second choke main jet
First choke air correction jet
Second choke air correction jet
Needle valve seat
1 F 2
1.7 (Ball type)
1 F 2
1.7 (Ball type)
170 (Ball type)
Car: This is the car that used this carb, this is a rough guide – for more detailed information you’ll need to dig into the workshop manuals. Reference: The Solex reference that is supposedly on the carb, not found it on mine yet. However, the venturi sizes are moulded onto the bowl either side of the Solex logo and that’s how you can tell which model you have.
The 197 (21-24) carb is sometimes referred to as a “Dyane carb”, probably because it seems to have first appeared on the M28 engine used in the Dyane. However, both 2CVs and Dyanes had this carb and then the latter – and more common – 225 (18-26) carb.
The top of the carb comes off with six screws – one of which holds the choke cable in place.
With the top of the carb off the fuel was siphoned out of the bowls – there was a bit of clart in the bottom of the bowls which I removed but nothing to worry about. The jets are easy to access with the top off and – not that I found any obvious obstructions – they were cleaned with spray solvent and some plastic brush bristles.
To replace the top gasket the floats need removing, the pin that forms the hinge is a friction fit and needs drifting out – I used a cross head jeweller’s screwdriver. With the gasket back the float heights were equal at 18mm so no problems there. Also in the top of the carb is the needle valve activated by the floats and, whilst that wasn’t obstructed, it was pre-emptively cleaned as well.
With the top back on the only remaining item was the new elephant’s knee which, being unperished, went back on much more easily than the old one.
* The pipe connecting the airbox to the carb, this is what I always called it when I was a nipper – no idea if anyone else calls it that.