u/Idiot_with_money

Hi,
Today I tried to use my new gaahleri airbrush (GHAD-68) and I have this problem with the 0.5mm needle.
The 0.38mm works perfectly fine. Only the 0.5mm setup seems to stutter and cause a reflux in the fluid cup.
So far I only tried water and Vallejo surface primer.
I already swapped the o-ring of the nozzle, still the same.
Is there anything I can try, or should I send it back (ask for replacement)?
Thanks in advance!
Airbrush: Gaahleri GHAD-68 0.5mm and 0.38mm
Compressor: metabo 220-24 (tested 1.5bar up to 2.6bar)
Paint: vallejo surface primer and only water