Accidentally getting a 2CV

[Foeux]

On 30/06/2026 at 20:13, Stinkwheel said:

Usually hot starting problems are coil related, but youve replaced that. 
Next bet would be fuel vaporisation, has it got its bakealite type insulator block between carb and manifold (ideally with a couple of gaskets as well) 

Did you do the valve clearances? Tight and they don’t start well hot either 

 

It has the insulator and gaskets between fuel pump and block. As for carb, not looked 

[Foeux]

23 hours ago, fatmanblue said:

I was going to say have you checked valve clearances?

2CVs can be buggers for hot starting, but as as @Stinkwheel says it's usually coil related (and dry coils have largely cured that.

Another thing I found troublesome was the ignition barrel. It's in the firing line for water leaks and mine had a tendency to cut the supply to the coil whilst operating the starter, making starting a fun* game. Binned it years ago for a toggle switch and a starter button.

Fuel pumps are not great, and any fuel line in the engine bay is past its sell-by date (if not already replaced).

Done fuel pump and all the rubber lines with proper fuel line clips...

 

[Foeux]

This weekend I will dump some fuel down the carb to see if it likes that when hot.

[Mad Cyril]

13 minutes ago, Foeux said:

Done fuel pump and all the rubber lines with proper fuel line clips...

Including the short rubber section above the fuel tank?

The only time mine has ever broken down was on a hot day in central London. It started again when it cooled down and eventually got us back up north.
The problem was that little bit of rubber pipe drawing air instead of petrol. No idea why heat was related but there you go, it's been fine for 15 years since.

[fatmanblue]

54 minutes ago, Foeux said:

It has the insulator and gaskets between fuel pump and block. As for carb, not looked 

Are there supposed to be gaskets between fuel pump/spacer/crankcase? I don't think any of my 2CVs have had them.

[meshking]

Some m28 engines have the spacer. My m4 engine does not, but that’s just quirky.  Some of the pumps have a thicker base so you don’t need the spacer, but in general I think there should be one.

Given lots of things have been replaced, I think checking the head bolts for tightness then the tappet gaps is the right move.

 

[Foeux]

21 hours ago, Mad Cyril said:

Including the short rubber section above the fuel tank?

The only time mine has ever broken down was on a hot day in central London. It started again when it cooled down and eventually got us back up north.
The problem was that little bit of rubber pipe drawing air instead of petrol. No idea why heat was related but there you go, it's been fine for 15 years since.

Not including the shirt but above the fuel tank. Thank you chum!

19 hours ago, meshking said:

Some m28 engines have the spacer. My m4 engine does not, but that’s just quirky.  Some of the pumps have a thicker base so you don’t need the spacer, but in general I think there should be one.

Given lots of things have been replaced, I think checking the head bolts for tightness then the tappet gaps is the right move.

 

Pie dishes off (got new gaskets anyway) and will check the tappets and head boots too

[Foeux]

Ahoy!

I've just looked at the carburettor and I would describe the vicinity of the accelerator pump as 'semi-succulent'; perhaps some fuel is drizzling out there it ought not to be (see pics). I'd also describe the gasket as looking old.

I now move my attention to the little bit of rubber hose on the tank (having a look in a mo).

In happy but non-problem solving news, there is an insulator block beneath the carburettor.

In further happy news, it started up first swing of the crank which is encouraging but cold start is not my enemy!

One more picture is provided for reference as to how bad the earthing issues were. The plastic surround for the heater control came pre-melted. This thing has really wanted to be on fire before!

[Mr Pastry]

Not sure where you are up to with the earth leads, but mine is like this.   

Yellow from battery terminal to bulkhead, then the larger black lead goes down to a stud on the gearbox cover.  That seems to be all it has.  If your black lead is disconnected, it would explain a lot. 

. 

[Foeux]

15 minutes ago, Mr Pastry said:

Not sure where you are up to with the earth leads, but mine is like this.   

Yellow from battery terminal to bulkhead, then the larger black lead goes down to a stud on the gearbox cover.  That seems to be all it has.  If your black lead is disconnected, it would explain a lot. 

. 

Thanks for making it extra clear.

 

I've gone belt and braces with thick wires from:

-ve to bulkhead 

-ve to gearbox

Gearbox to chassis

So earth's are definitely no longer an issue.

[dollywobbler]

If you've had electricity issues, there is a possibility the 123 has been mildly fried. Early 123s could be very problematic when hot. I once blew an exhaust crossbox apart because it just wouldn't provide a good spark. Until it suddenly did...

If you've still got the points set-up, I'd be tempted to refit just so you can prove (or not) whether the 123 is at fault. Alternatively, keep a coil at hand and just swap it as another avenue. Never assume new is good.

[Westbay]

Does look like the weeping accelerator pump (knackered diaphragm ?) combined with it's location above the exhaust manifold may be encouraging a heat induced vapour  lock ... 🤔

[bangernomics]

Have you got an original carb on it with an accelerator pump? Maybe worth seeing if the rubber has split?

Echo Fred. Very common on a/c beetles too.