Search tags only

I am trying to set up the search function to only search tags I’ve assigned to pages. I’ve weighted tags 100 and the others to zero and added the tag id to the first option under restrictions to limit the search to just those tags. The problem is it’s still searching everything and coming up with results for keywords that are not tags. I’ve temporarily gotten around the problem by taking everything except the words I want out of the index, but going forward this is not going to work.

https://wordpress.org/plugins/relevanssi/