Something to consider. For the best images, the transduer needs to be parallel with the water's surface when you are scanning.
Most boats sit on the water with a bow up attitude when idling with the outboard. Base your attachment on that premise.
You can't get that attitude under the step unless it is reversed from how you are holding it.
Additionally the farther from the hull bottom that transducer is, the slower you will have to go to get clean non-aerated water flowing across it. The transom step creates a vacuum when you are moving forward.
Marine sonar won't work through air.
The best location for the fastest scan speed and still have the transducer protected from possible impact damage is above the hull drain. BUT that will depend on the waters you fish. If you fish in timber/stumps a lot, you may want it on the metal flake a little more to the left just below the motor mount bolts. That will give the left side scan pulse a better "view" past the motor mount, but not so close to the lower unit that it will hit the transducer when trimmed all the way down. You will have to trim out some when scanning if you put it on the transom, probably not if under the transom.
Trim your motor all the way down to check the clearance.
