Oven temperature too low

OK here is a follow up on my Wedgewood oven: there is a slotted screw behind the control knob. According to the manual it is only to adjust the pilot light, not the burner. The pilot flame looks good and lights easily. The pilot flame increases when the temp is moved from pilot to a higher setting just as it should so the secondary pilot is working. Turning the temperature to the desired setting the burner lights after 45 to 60 seconds also as it should but shuts off before the temp gets to the setting. This, I believe rules out problems with the safety valve. Also the burner burns continuously when set to broil. I guess it needs a new thermostat; however it appears that the replacement has been discontinued. I have called the local RV repair shops and have searched the internet but have had no success as yet. Any suggestions?
Stan