Ford: 1985 F-250 4.9 liter starting/Ignition, f 250, body style

Question
I just purchased a 1985 F-250 with a 4.9 liter motor(replaced with similar), which has the same problem as a 1982 F-250(351 c.i.) I looked at. When You turn the key to start the motor it cranks as usual, but when you release the key and it returns to the run position is when it starts. I would appreciate your assistance.  

Answer
I have seen this many times with that body style of truck the ignition switch tends to sometimes gets out of adjustment or in need of replacement. there also could be something broken in the column that is not allowing the switch to operate properly. the ignition switch is located on the column almost at the bottom . you can watch when the lower cover is removed to see if everything is nice and free if it is jumpy then there needs to be servicing done to the column. Hope this helps.

Jim