How to do short RSS comments

I'm trying to do short RSS comments so readers will come to my site to read the entire blog. But it always shows the entire blog in the comments.

A previous post suggested editing /conf/_formatting.php and changing $rss_excerpt_length I've tried this and it makes no difference.

Any suggestions?

Did you read this post:

And can you give a link to your blog and your feed so I can see if it's just description, or if the content:encoded section is full-length, too.

This is my feed : http://www.tenderfeelings.be/blog/xmlsrv/rdf.php?blog=2
and it is set to 50 words.
When I look in to it, I see my description is shortend but the post itself is not....

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