yours is finished
SORRY, THIS IS FOR THE O-RING ONLY. THE IDLE SPEED SCREW IS NOT AVAILABLE NEW, YOU'LL HAVE TO FIND A USED ONE.
We’ve seen people use silicone, teflon tape and even loc-tite to make it stay in place. Don’t do it.
It’s simply the o-ring the on the adjuster screw itself. Yours is old, crunchy, hard and compressed. Replace it to keep the idle speed screw in place and sealed up.
Choose the "shipped by-itself" option if it's the only thing you are ordering and I'll send it to you in an envelope or "with other items" you are adding it along with your order of other goodies.