Centrifugal Adjustment Help!

When you rev up the engine, does the outer bell on the CC spin?
Can you see the weights moving out and the friction material gripping the bell?
It's quite hard for that not to work, it's simple physics, and so simple in construction, I can't see how it would not be able to work.
There are some reports of the spot welds missing or breaking that holds the drum to the small gear on the CC, although all the ones that I have seen are pinned/riveted.
If the bell is spinning with revs, then it should be spinning the big gear on the manual clutch, so you need to looking at the manual clutch system for the problem.

Which screws? The ones holding the outer cover?

Maybe a wee bad of penetrating oil will help loosen them up?

I really stubborn screw may need coaxing from an impact driver like this:

Impact Screwdriver Set with Case

Maybe your manual clutch pucks are glazed and its slipping? Or the flower nut needs to be adjusted on the manual gear. Like rohmell said, the CC works by simple physics.

Or mabe the cc is slipping on the shaft?

Yeah, that could be happening too. When you put on your CC did you make a notch like the manual clutch so that little key thing on the shaft can fit on the CC?