A C525 Captain reported overshooting the 1;300 FT TEB DALTON SID mandatory altitude by 140 FT when the aircraft's owner was flying the aircraft and was slow to respond to the level off command.

Narrative

We departed Runway 19 out of TEB. We were given the DALTON SID. The owner of the airplane who is a pilot asked to fly the leg home. I; the Captain who have flown with him before; agreed. After takeoff the clearance is to climb to 800 FT then a right turn to a heading of 280 and continue climb to 1300 FT. After 800 FT he made the right turn to 280 and continued climbing to 1300 FT I noticed that he pulled the power back and started to level off. I called out 100 FT to go and felt that he was not leveling off quick enough so I said it again but at that time it was too late; he had climbed past 1300 FT and was still climbing. I took command of the airplane and leveled off; but by the time I recovered; we busted altitude. Tower called during the climb and told us to level off at the mandatory altitude of 1300 FT and told us to respond. I did and there were no more conversations regarding the incident. In the future I plan on flying the airplane myself where there are such tight restrictions on heading and altitude. I don't mind letting the owner fly but it is my license on the line.