Rotate Y over time

There is lots of post on this and I cant get it to work

 function Increment()
 {
     Count++;
     if(Count == CountTo)
     {
         //if(Gate.transform.Rotate != (0,90,0))
         //{    
             Gate.transform.Rotate(0, 90, 0);
         //}
     }
 }

That is what I have currently. It just goes from A-B instantly.

If I move it to update() and use Time.deltaTime * 100 in the Y it does nothing. Am I missing something stupid?

Also, I know my commented out if is bad. I am also looking into querying the Y value alone.

Any ideas?