More tag in excerpt when manualy inserted in new post page

So, I’m using the excerpt to display part of the post in an archive. For non-archive pages I use the content. But when I add a new post, type something, add a more tag and type something behind the more tag than the excerpt will only display te post until the more tag, but it won’t display the more tag, because there are not enough words before the more tag for the excerpt to display it’s own more tag.

I want to display a more tag inside the excerpt when I insert one inside the add a new post page.

I’m building a theme on my own localhost server, so I can’t put in a link to show you the problem. I also do not have web space to put pictures online so I can show you the problem, but I do hope you understand my problem. Please, help me.