Note the screw runs through two "arms" of a U-shaped bracket. There is supposed to be just enough interference to prevent the screw from moving freely.

Remove the screw, and then take a pair of vice-grips and clamp the two arms SLIGTLY together to add a touch of interference. Then reinstall the screw.

Jon.

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop