I haven't started to look at the MC harness but the new harness kit that came with the American Skier had a confusing amount of plugs. Still, the adapter harness for the single puck was designed to for unplugging the triangle plug to the ecm, plugging the adapter harness in both male and female sides as a jumper and doing the same with the power rectangular plug. I clearly see the female triangle plug from the adapter harness open and a male triangle plug open from the boat harness (although I can't see the wire colors on the boat plug to make sure they match). I also see a male power plug open on the adapter harness. It's possible that your ecm is not getting connection and your puck is not getting power. Explains the symptoms. But your wiring harness could be different.
Note that it's very confusing. Splices are hidden in the wiring harness. Some plugs are redundant or for occasional maintenance use. That's why I made a simplified harness for the American Skier (which has no plug to upgrade - so much for that idea). I haven't looked at my MC yet to try to figure out it's hookup ( @Xpropman it will be a while before I get a chance to look at it - in the meantime, I'll just use the spare old style puck).
Note that the triangle plug really has only two wires used, the blue/red and the blue/white and the rectangular power plug has only three wires used, the red, black and pink. The white/red and white/black wires were dummies on my harness.
Good luck and keep us posted on your progress.
Eric