When I release clutch/brake pedal or push clutch lever up the engine on my craftsman tractor model 917.273399 turns off. How do I adjust the clutch/brake pedal so engine continues to run?

Hi,
This is normally an indication that you have a problem with a safety switch. The mower must detect the presence of the operator on the seat when the clutch is released or the blades engaged. That makes the seat switch a common culprit.
This can be verified by unplugging the Black wire near the starter(accoding to the schematic attached.) The problem should vanish, but the key switch will not turn it off. That can be accomplished by plugging it back up. Then you must find the failed switch.
Peace,
Clarke

Thanks I will check to see if I have a bad switch.