This looks very much like an issue that I had with firmware retraction a little while back. The problem was caused by the default value for extra length on unretract being set to a non zero value. So, I was retracting 2mm but unretracting 3mm. Your comments back up this hypothesis.
So look for anything that could be causing the extruder to do extra length on unretract. I you are using firmware retraction, set the R parameter in M207 to 0 (zero). If you are using David's latest firmware, it should now default to 0 but set it anyway just to be sure. If you are using "normal" retraction, check your slicer settings for anything that does similar. e.g, in Slic3R there is a setting under "Extruder" called "Extra length on restart" Make sure this is set to 0. Also, disable any pressure advance settings, either in firmware by commenting out any M572 commands, or setting any slicer settings to 0. HTH
Thank you for your input!
I´m no experimenting with flowrate and are down to 85% and I´m not getting the blobs anymore.
I have a theory that the flow was to high and eventually it gets to high and press out all the filament at once… I´m not used to bowden setups but my feeling is that this can happen with a bowden tube. What do you think?