Someone knows of algun tutorial to modify an engine weed eater in order that it has mas power?

Plenty of guys on here have played with all types of weedy motors in the past and a few of us are still having fun with them!
If you can tell us what motor you are starting with, more than likely we can point you in the right direction.
It is all too easy to go backwards with your mods if you are inexperianced then have to go looking for another motor!
Better still post up some photos of your engine as there are multiple engine types when it comes to several of the brands even in the same cc class!

Chad.