I have a Toro Z 253 62" mower. Never had any issue until just now. The thing started shutting off on me UNLESS I applied the emergency brake. Even with the control levers out, I can't run the machine unless the brake is applied . I even tried to rig to finish mowing and taped the button down but then the control lever safety kicks in..... and my mower shuts off. What the heck, any help would be much appreciated! I am dead in the water and a mchine in the field.