figure out this damper

I have a two-zone system, the upstairs damper seems to be fully open at 1/4 way turned. Is this possible?
It is an ARD16 and the motors are set up for spring closed. The lower floor works okay. I took off the motor on the upper and with the shaft all the way clockwise (supposedly closed) it is still partially open. As I turn it CCW, after about 1/4 of the turn it becomes full open. I say fully open based on the decrease in air blowing out of the anchor hole. Then continuing, to partially open again.
There seems to be no position that is fully closed. And with 1/4 turn being fully open I can't figure out how to get the motor to do what it is supposed to be doing.
Is there something wrong with my damper... or something wrong with my analysis?

puttster