Your engine is boiling fuel out from carb. Then, on 2CV, mechanical fuel pump need to fill carb again before it can start. As I mentioned earlier, that same issue is on my both carburated car, if I start without waiting te electric fuel pump is filled carbs, if I wait enough (hearing the sound of pump change, frequency drops), there is no issue with starting. Both have V-engine, so the thermal issue is worst when the carbs are top of the engine...

So, without fuel the engine can't start, and you need to crank to have some fuel on carb...

If that is the case, how can it start right up with no problem after it has cooled down for hours? The carb would be just as empty.

Well that's a good point. My theory was maybe the fuel is boiling, being forced up through the jets, into the intake manifold and ending up in the cylinders wetting the plugs. I don't know if that's possible.

I thought the hot start issue you guys were talking about was either a weak spark or no spark when trying to restart the engine after it has been parked for 15 minutes?

If the coil was getting too hot, looks like the engine would misfire or quite all together when going down the road.

I don't think it is fuel boil off as it starts immediately when I change the coil - It only takes a couple of mins. Anyway, I have bought one to the ECAS dry coils and will update you when fitted at the weekend.

Confidence is high.

One thing I thought I might try for kicks is to mount a small 500 cc tank near the a carb, and tie the fuel line into it. Or just fill it with some rubber alcohol.

Mount a windscreen washer pump in the base of the tank. Power the pump using the wire going to the starter solenoid. Or use a push button.

Mount the windscreen nozzle in the air cleaner so it shoots fuel or alcohol into the throat.

When cranking, the pump sprays the fuel directly into the carburetor.

Yes or it's catches fire....
We did a try with pouring some petrol on the filter to start a 2cv. It started well but the airfilter flew burning though the garage...

I can see that happening!

A better idea would be to squirt the fuel into the intake manifold through a vacuum port or through a vacuum port on the carburator. Use a valve to adjust the flow.

On problem is I don't think there are any vacuum ports on the intake manifold or Solex carburator since these engines don't have a vacuum advance or emissions.

And ideas on that one?

Here is the washer tank I installed in my Trabant that could be used. Although I think you can get thse cheaper. I think I paid $US 12 for mine.

https://rover.ebay.com/rover/0/0/0?mpre ... 2434953896

Hmmm
I'm trying to figure out why you are trying to add fuel to an engine that is probably already has to much fuel.

My experience of starting 2cv engines when they are hot is to start with full throttle. Get as much air in as you can. I put the pedal down slowly or it pumps more fuel in. On the other hand, if want to add fuel, pump the pedal and avoid setting fire to your air filter.

Well the thing is I'm not sure what the problem is. I'm not sure if the fuel bowel is empty (as well as the combustion chamber and plugs) or if the plugs are wet.

I guess removing the lid off the fuel bowel may give me some indication of what's going on.

I was discussing this hot starting issue with one of my Ford Fairlane friends several years ago. He said one day he decided to remove the float bowel lid to see what was going on. He said from where the engine heat soaks after shutting it off, the petrol in the fuel bowel was actually boiling!

I wouldn't think this would be as much of a problem in the U.K. as it would be in the U.S. When I was over there in July the average high was 20 C. That's the average low in the July where I live!

Of course the other alternative is to just hit the starter and let the engine spin for 30 seconds then when it tries to start, floor it. It seems flooring it while cranking just dumps more fuel into the engine and aggravates the problem.

One day I was in my Trabant and it was a blistering 36F. Stopped by the petrol station to something to cold to drink, came back out within 10 minutes and the car would not start. I managed to get it started by spraying some ether into the air cleaner hose. Maybe in this case, the plugs were wet.

Yeah I realize starter fluid is normally used to start engines when cold not when they are hot.

My guess is ether is so volatile it will practical ignitte on compression alone.
Then once the engine get's spinning, it cleans off the plugs.