I know pretty much nothing about these heads Max, but isn't it usual for the head to only turn in the winding-on direction except when you loosen the large locking nut at the bottom of the head, to unlatch it so it can feed one notch, usually with a bit of juggling to make it do so? The main challenge is to get so good at the juggling part that you can get it to feed before the engine clogs itself up and stops. If he lived in modern times, Dante Alighieri would have added an eighth circle to his conception of hell, where poor benighted sinners struggled perpetually to get any useful work out of line trimmers.
