I have a older Dixie gas stove I have the burners working good but the oven will not work proper.The pilot will light when I turn it to "on" but the burner in the oven also lights. just a little blue flame. I can turn the oven up to 250 and it will reach 250 and keep on getting warmer in the oven. this model has no safety gas valve in front of the pilot just the pilot and burner.How do I get the oven so it will turn the gas on and off when it is needed when cooking?