If you want to embed a specific part of YouTube video, here's how you should edit the code, just append &start=[number of seconds from the start of the video] to YouTube’s URLs.
<object width="425" height="344"><param name="movie"(value="http://www.youtube.com/v/abcdefghijk&hl=en&fs=1&start=15"></param><param name="allowFullScreen" value="true"></param><embed src="http://www.youtube.com/v/abcdefghijk&hl=en&fs=1&start=15" type="application/x-shockwave-flash" allowfullscreen="true" width="425" height="344"></embed></object>
For e.g., in the Google Chrome's launch video below, we’ve skipped to the last part, where Sergey Brin answers some interesting questions.
YouTube doesn't provide an option to link to a part of the video, but you can still use the embedded player:
http://www.youtube.com/v/w8oPEJiCqi4&start=249&autoplay=1, where the autoplay parameter is necessary to automatically start the video. Since there's no end parameter, you can try Splicd, a site that uses YouTube's API to isolate a part of a video.
More info: YouTube embedded player parameters
Source:→ Google System