We have an older 4625 which has been a good unit till now. When I last used it and went to turn the key off--it would not shut off. We idled it way down and forced it to quit but trying to move forward and using the hydraulics at the same time. I am thinking it may be the switch but do not know. I restarted it a day later and had a devil of a time getting it started. I had to hand pump the fuel for a long time. Also the hydraulics wouldn't "unlock" when I restarted it and the throttle did not seem to cause the engine to increase R.P.M. Anyone have trouble shooting ideas?