I just bought a used 99' 751 f series with 400 hrs on it. When i was test driving it, and turned the key off, then engine shut down slow (over 3-5 seconds or so). I thought it was some special shut down option. Now after picking it up and using it a bit more, when i turn the key off the engine shuts off immediately every time. Is this normal? Another question of mine......Why on the engine door does it have a maintenance schedule for a 753?