Hi Wylton,
Did you clean (with the wipe Mike sent) the belt as well as the pulley and inner platter? I used latex gloves** when I fitted the belt.
**Although I fully accept that perhaps not everybody has box loads of latex gloves in their household.
We have them for when we give Zebedee (the cat) his chemo pills.
Regarding speed adjustment, I’m not sure which bits to twiddle, but hopefully Peter Swain’s excellent ebooks might hold the clues. I think I read somewhere that the belt is supposed to run on the widest part of the pulley and one checks that by putting the outer platter on upside down, such that one can see what the belt is doing - before wielding the screwdriver!