The oven burner would not ignite

Removed oven door, warming drawer, oven bottom, oven burner, disconnected wires to igniter. Also, instructions said to turn off gas supply at pressure regulator, {little red lever.} I also turned off main gas supply, and un-plugged power cord. Removing the igniter and replacing with new one was easy. Splicing wires and putting everything back together was also pretty easy. The only problem was when I tryed to open the gas to the pressure regulator, the little red lever popped off. Very cramped area to work in, could'nt get a tool to fit in there. So, I got some nylon string, made a loop, looped it on the notch on the pin, pulled it out and got the little red lever back onto the pin and then was able to open the valve. There is no gas going to the burner if that lever is not on holding the pin out, and you can't put that lever back on unless the pin is pulled out. If I ever do that job again I will not touch the red lever, I will just shut off the main gas supply. It would have been a pretty easy fix if that lever would not have popped off.