Have Guardian/Generac 7K standby generator 7 yrs; recent problem: Starts weekly excercise, runs 20 seconds, shuts off; low oil lite on.

Also have replaced oil pressure sending unit along with oil change & filter. It will run about 1 min. when restarting, then continue to run on third attempt. No knocking, excessive noise or vibration. It has run for several hours once I have started it manually. During the hottest, dry weeks of summer it performed its excercises normally.