If anyone is having trouble with there older Jessem Rout-R-Lift FX adjustment not staying put, this is how I fixed the one I have
1st I replaced the adjustment screw with one about 3" longer and added a 3/4" dia. piece of rod on the bottom end.
Router Clamp 2.jpg
Then I made a clamp fastened it to sides of cabinet but it could be fixed to the legs if yours is on a table
Router Clamp.jpg
Then with a knob as in the picture it's just a matter reaching under the table and tightening it after you make your adjustment
Router Clamp 1.jpg