Stone will not turn if you put too much pressure on it

[Cliff]

I have an older Super Grind 2000, I haven't used in quite a while I started sharpening a chisel and as long as I did not put any pressure on the stone it worked ok however I seam to remember that I could the last time I used it  I removed the honing wheel and drive wheel turned the motor on and used an emery cloth to clean the motor shaft then replaced the drive wheel and used the emery cloth to clean the surface however this did not really help much? wondering if someone has more suggestions? other then replacing the drive wheel.

Another question, when I turn the switch on the stone does not move I need to push it then it gains speed and runs ok.
Another question, is when I turn the switch on I can turn the stone in either direction and it will keep turning the stone. Is the motor meant to run in either direction?
Thanks
Cliff
Carlisle Ontario
Canada