Video doesnt work if using exact seconds

Read the discription 🙂

You can also start and end each individual video at particular times. Like the above, each option should begin with ‘&’

start – Sets the time (in seconds) to start the video. Example: http://www.youtube.com/watch?v=quwebVjAEJA&width=500&height=350&start=20
end – Sets the time (in seconds) to stop the video. Example: http://www.youtube.com/watch?v=quwebVjAEJA&width=500&height=350&end=100

Using : &start=20 tags