mosquito hotend flow rate

mosquito hotend flow rate

I have a mosquito hotend and the flow rate seems really low.  I'm running a .4 nozzle and can't seem to print very fast without the extruder jumping on the filament.  I have tried two new nozzles.  I have check steps on the extruder and they are correct.   I am using PLA material 1.75.  I have raised the temp and nothing seems to be helping.   I can slow the print to 40 mm's and that seems to help.  It's also under extruding.  So I can't raise the multiplier as it just won't flow like it should.     Any idea's?

Thank you