https://si.shimano.com/pdfs/dm/DM-FD0002-05-ENG.pdf
First off, make your life much easier and install an inline cable tension adjuster.
Check the cable routing. Also, if the bike has a braze-on type front derailleur, is the support bolt contacting the frame by a support plate? Doing so makes it easier to microadjust the yaw of the derailleur and also greatly stiffens the derailleur for shifts onto the big ring.