If it is this one 
just mounting the Z-motor on top will not work.
While turning clock wise, it can push the router up, but since the depth-stop can’t be locked to the base, it can’t pull the router down.
You will be able to use this router without the base, by going for alternative z-axis like
- the-meticulous-z-axis
-
yet-another-z-axis-mod
or a similar modification for the z-axis.
Kind regards, Gero