Usually the blade needs to be turning pretty well before the controller will " kick in " and start putting out decent voltage. If you don't have a strong enough, steady wind, the genny will immediately start stalling the blade speed and cause "cut out". Think of your blade assembly as a flywheel and what it needs to stay spinning when the genny starts charging. I would guess closer to 10 MPH steady winds to overcome the cut in voltage.
This is not to say there is nothing wrong. I would leave it up and see what happens.
In the days of generators on cars, instead of Alternators, if a generator was "motored" to be sure it was working, once installed on the car, you needed to "Flash" the controller by physically opening the points in the controller and then letting them snap shut. It's been over 50 years ago that I remember doing that, just not quite sure I said it correctly.