I've managed to turn the pilot ON but the burners don't come on even after I turn the temp. To 90D on my TM? Also, the pilot Knob is missing a screw (I can pulled it off) and some sort of plug? (there's 2 holes on the sides of the Knob) does anyone know what kind of screw fit in there and what goes in those holes? Lastly, I can smell gas, I sprayed a soap and water mixture as advised and notice bubbles coming from the side of a metal plate which the pilot Knob sits on. Should I replace the entire valve?

Any advice will be greatly appreciated.

Sounds like a very old furnace, when gas furnaces get old sometimes they can get very dangerous,, I believe I would have a professional come out to help you, the life you save could be your own,,