My Abu Garcia Revo STX isn't quite as smooth as when I first purchased. Actually it is considerably less smooth. I haven't fished it yet so I don't know what is wrong. Any tip to make it more smooth or return to factory quality.

Have you lubed it or taken it down to see if there is too much lube? How dirty is the reel? Was it dropped in the water or rained on hard?

I know after using mine in the rain, it felt that way. Took it down, blew it out, cleaned lubed and it was like new.

clean it!

I have cleaned it a lot. However I have noticed that when I loosen the tension knob it is smoother than when I tighten it.

Well yeah that's how it works. Nothing wrong with your reel.

You said you haven't fished it yet but you have "cleaned it alot" if it's never been fished why cleaned so much are you sure you put everything together right.

Quite possibly, you used less lubricant than the factory did, hence the "geary" feel.  Under load it will also feel less smooth than when spinning free—that's normal, as TNBassin' said.

If you havent fished it, and it hasnt gotten soaked or something take it apart and reassemble with oil and grease.  It should be just fine.