So I came across an add that this was on sale for $149 . Went ahead and ordered it but I am now wondering if it is license restricted to only one engine, like can I use it on multiple different boats?

you can move it from one boat to another. Its not restricted to one engine. It simply broadcasts some of your smartcraft info to your mobile app.

Yup. Like obrien said, just unplug it and plug it in to whichever engine you'd like.