Question about Primus OmniFuel II

Does anyone else have problems getting the burner to work with petrol? Despite the correct nozzle & long preheating time (>5min), I can't get the burner to work properly. It seems as if there is too much pressure, as the flame "blows itself out". But according to the manufacturer, too much pressure is hardly possible, and all other steps were followed correctly. I also cleaned it well...