If you are talking about the little metal spring-like piece that fits on the flat of the inside of the knob and keeps the knob on the valve stem it has nothing to do with the flame staying on. All it does is stop the knob from turning on the stem. A little piece of cardboard or toothpick will keep the knob on. I lost
a knob and just used the stem, a bit hard to grip but worked ok until I got a replacement, not Force10 but off a barbeque.
All the burners should work even if the knobs are off. If yours won't stay on you have another problem.