mf35 no engine speed on pto

Hi, my name is Paul and I have just bought my first tractor, a mf35 to do work on our hobby farm. I do have a problem with the pto drive tho'. I cannot get it to turn at engine speed it will only drive at ground speed, even when the selector is at engine speed ground is all I get. The selector seems to be engaging ok, I'm wondering if I am doing something wrong. Any help would be great.:thanku: