First let me say I have little experience rebuilding stoves beyond replacing gaskets/seals. I recently bought a pretty nice Optimus 8, believe it to be mid 40's to early 50's. Nickel tank flat slotted fuel cap. fully embossed case. Any way I have refreshed the fuel cap and pressure relies valve. My question centers around the control knob. On my 8R's I have about 1 turn from closed to fully open. On the 8 the control knob spins for many turns. Does this mean I need to repack the stem packing? If so what is the fix I need to buy/ What stops the knob after 1 turn on my 5R's. the packing? Thanks.