Reading on every site about front dérailleur adjustment, the distance from the bottom of the outer dérailleur plate to the bigger crank cog should be "one penny".
Mine is around 1cm! it does shift OK. not perfectly, i have to spin it very slowly and constant for the chain to move. but works. never dropped the chain or jammed.
The front dérailleur is a Shimano FD-MT60-AL, Deore (if you look at the pic here, it's showing a much closer distance, but it's also showing a rusty chain... so I will not mimic it right now :)
The crank is a biopace
Here's a pic of my bike. Since the crank is not round, i've set it up on the "closest" point to the derailleur
Here's another pic.
Another angle. There's no height adjustment, and there's no mark on the frame suggesting it ever was at another position. Can it be some lack of lube internally or bad cable messing things up?