OK, will go further
First of all, I must apologize for my long tonque. It will never happen again.
NO. The engine does not work smoothly at any time. It starts and works ONLY if accelerator is "in floor". Works for about a 40 sec. (not more) and then: RPM kicked down once (for a 1000 I think), 10 sec, then once again and... dead.
The fuel pump works normal, we tried to close the jump to be sure the fuel is delivered all the time the engine runs.
Well, we'll do the second test and post the results.
P.S. I've found this thing: on the ignition distributor there is a vacuum corrector. It has two connections. We connected one of them to the input collector (as done in russian cars) only for ignition advance. Yesterday I've found in the Inet a scanned page from MB manual: it has two chambers (advance and retard) and they must be connected to the three-way valve. We got only one such valve: on the wall near the front window. Too far I think. Is this correct connection?
P.P.S. Remember, I've got photos...