Amp test on the generator

[Merc Cruzer]

Preliminary test seem to show that the battery is not charging when the rpm's are increased to 2000.

As you can see I would like to perform an AMP test on my generator with my Sears engine analyzer (that I have had forever). The question is what terminal do I put the the "shunt" on: red arrow post, white arrow post or black arrow post?

If additional photos are needed to answer, let me know.

Found this on Utube, interesting: https://www.youtube.com/watch?v=RjLW_eb3D-c

Thank you,

Merc Cruzer