P-C 890 plunge router problem

[Gary Rose]

The plunge lock on my 890 Porter-Cable router creeps while in use. I've tried adjusting it, using the owner's manual, but the instructions don't really tell you specifically if the rotation (cw or ccw) that you're using is tightening or loosening the mechanism and they don't tell you exactly what the function is of the large hex nut vs. the small internal set screw. I think if I had an understanding of this I might get the mechanism adjusted fairly quickly. The way it is now I'm doing a trial and error method with mostly error. Can anyone clarify this for me? Any help would be much appreciated.

Thanks,
Gary Rose