On standing pilot ovens the maker uses a safety device to kill the gas in case the pilot blows out. As long as the pilot is lit the gas safety magnet hold the gas flap open inside the safety valve.To save energy the pilot has 2 flames. The standby pilot keeps the cooper/nickel probe/sensor warm so the oven will light faster, the 2nd pilot is much larger, only appears when the oven control is turned on and this is what opens that valve. So when you turn the oven knob on the gas leaves the control and goes downtown to burner land. If that pilot is lit and that slow opening flap inside that valve is open, then the gas will enter the burner tube and ignite when it hits the pilot. Pretty slick ain't it? So what can go wrong? With age the flap inside the safety valve
will wear out, get weak, work a little, then take forever to light and eventually just goes bye bye. When you get ready to replace the valve it ain't gonna be adjusted exactamundo, you gotta tweak it. To do so after bubble testing for leaks and lighting the pilot you turn it on and observe the flames. It needs to be not more than half way up the flame spreader. If it is to small of a flame it will take forever to bake even a pie shell, if it is too much their could be burned bottom and in some cases fire hazards. OOPs.