Standard YouTube shortcode:
To make it start from a specific point when you click the play button, you change the shortcode to this:
Where NNN = how many seconds from the beginning of the video.
I want to embed the video http://www.youtube.com/watch?v=owGMZ6yJ57o, but make it start at 1min 38sec. I’ll write:
Result (enjoy the orgy):
Note 1: If you’ve seen a different suggestion (video URL followed by #t=1m38s), this is used when you want to link to a point in a video, not when you want to embed the video.
Note 2: For other Youtube shortcode options see Support doc on YouTube.