I'm not quite sure what you mean, delay time? You mean like a generator? I'm guessing if you pick up an airboard the 'delay' is the amount of time it takes to get back. It sounds too obvious, but I'll say it anyway.

Remember that the airboard event is 'Environment --> Object --> Airboard' in the event list. Funnily enough it gets removed when you say the level is multiplayer in level properties. You can get it to generate like any other event and set the delay in that way.