The injection pump timing should not prevent the motor from starting, the motor should start and run no matter how the pump timing is installed Incorect pump timing will reduce the engine performance not keep it from starting. I have never dealt with Hans, but I can't imagine an experienced rebuilder making such mistake.
I think you have air trapped in the injection lines. Use a remote starter button connected th the cold start valve to inject 1/2 second pulses of fuel fuel into the motor while cranking untill the motor starts and stays running on its own. It can take a while before the air is completly worked out of the lines. Don't overlook other systems like the fuel pump, fuel pressure, ignition timing, spark etc.