Exisitng post will not remove the More tag

I wanted to remove the more tag from my posts and have the ability to only manually add it. Everything I read and tried didn’t work so I gave up and moves on to something else. Then I added a new post and noticed no “more tags” appearing. All my new posts I have to manually include a more tag (which currently appears as just text). The problem is my original existing post which I was checking everything against to see if it worked will not remove the more tags on my page.
Why is this? I have refreshed everything checked on other browsers and they all are doing the same thing. Any posts shown on a new blog page have the more removed but the existing page will not transform, it refuses to change. All css is the same for all pages. I am just curious if anyone else has experienced this problem and how best can be assured that what I am coding is working?