A half turn may be too much.It might be ok for the first adjustment, but each subsequent one could be 1/4 turn.And probably no more than 1 turn all together,or I would suspect a poor quality rebuild.It's not hard to get that right, on the bench.
However, since we now know it's power assisted, bear in mind that air in the system will also make for poor returning. And the Federal pump is often lazy in the first place. I have found the Saginaw pump much better in every way.
