So there is no confusion to what I asking about. Here are a couple of pictures the the old choke pull off.
The first picture is without any tension on the stem. The second picture is pulling out the stem and compressing the internal
stem spring.

The FSM says:
"Note that most units, a cylindrical stem extends as the internal spring is compressed. This spring must be fully compressed for proper measurement of vacuum kick adjustment".


My interpretation of the FSM instruction would be that the while vacuum is applied to the choke pull off. The diaphragm stem would need to be extended while setting the choke gap.

Agree?