Check out http://dailymanga.org/
I went there and looked. There are some groups scanlating it, but they didn't start at the beginning.

http://www.shonenjump.com/mangatitles/ygo/manga_ygo-om.php
Issues 9-23. I think it's just 1 chapter per issue. So it's probably missing some chapters.

http://www.janime.net/
But they are not consecutive.
Chapters 50-53, 134-146, 191-200, 280-285.
Or the RAW "Japanese" from Chapters 279-343

http://jenniyah.cjb.net/
Chapters 206-343