accellaration problem in hot engine

[peter de jong]

Hallo,
4cv 1960 with ventoux 670-1.28 IBT carburateur. Cold start fine, after 20 minutes when de aut choke goes down, accellaration is completely lost.I am in France, so many advice. Cleaning carb. changing condensateur, new points etc etc. No effect. Do I miss something?? No air leaks, running into the warned for aut choke problem??
Thanks on forehand, Peter de Jong

 

[malcolm]

Does the 4CV have a vacuum advance on the distributor? The R4 with the 680 engine doesn't have the vacuum advance and I assume yours is the same.

If your engine is like the R4 engine I would suspect a partly blocked main jet in the carburettor.

Remove the carburettor, unscrew the jets, and blow through the holes with an air line. My guess is the jet at the bottom of the float chamber has a blockage. On later cars there is a brass plug at the side of the float chamber that needs to be removed for access for a screwdriver to unscrew the jet. I don't remember if early cars are the same.

 

[peter de jong]

accelleration

Thank you Malcolm, you are right,there is no vacuum.
I thought I cleaned all the valves, but I did not take the carb off. On the motorside there is a valve to screw out I did and cleaned it. The funny thing is with a cold start it runs like hell for 20 minutes. Regulating the mixture when it is warm of course the stationary run is good, but even with I think a rich mixture mimmicking the shoke situation it turns off when I try to accellerate. I re-adjust the points to 0.4 and I have to get my croisants with a cold motor.
Of course the regulator needs spanking once and a while , but I d'ont think this is the cause. also with or without a gas-filter there is no change.
I will take the 28 IBT off and clean everything again,
Behind the aut choke is a blokking screw wich hold a cylinder on a spring, any idee what this is??

Thans on forehand.
Peter

 

[peter de jong]

solex 26 DIS

The accellaration story is going on. I changed the bobine because it was very hot during running. Other advice change the carb. to 26 dis with handchoque.
This is expensive (250 EURO) and fits the carb on the 845cc of the ventoux?
Also they say the SEV junior should be changed for the Ducellier with the petit pied /axe.
Any advice ?
Thanks Peter

 

[Le Champ]

Could be an ignition coil problem - swop it to test. :smile: