Mixture adjustment screw caps

I just bought some new caps for my mixture adjustment screws since the old ones cracked after 41 years. The new ones are a hair too big and feel like they are just going to fall off. Anyone else experience this? I was thinking of siliconing them on. Thoughts?

The caps need a little pressure to fit and seal. Don´t risk any damage to your carbs and put in a drop of sealant to secure the mixture adjustment screws .