I have a 1973 XJ6 with a broken AED unit. This means the car is difficult to start from cold. My local mechanic insists that the AED is a disaster guilty of many engine break-downs in the old days. So, to rectify my problem he did not recommend the installation of a new AED unit - although these are still available - but simply bypassed the old one with a valve that one has to open and shut manually: When starting from cold, open valve; when engine is warmer, close valve so that the carburettors constantly get the right amount of fuel. However, this "fix" is far from perfect. The car is still difficult to start when cold and the engine runs very roughly and unevenly until it is warm.
I am no expert on this so views are very welcome. Do you agree with my mechanic that the AED unit is total crap that should be avoided at any cost? Or should I rather install a new AED unit and hope for the best?