Welcome to the Forum!
What you are describing is that you do not see a rooster tail out the back. Some people modify their jetskis to eliminate it, some people like them some don't. But its a preference I guess. In your case I guess either the hose from the propeller nozzle housing fell off or the hole that the hose is connected too got stuck by something and is not letting the water to flow out. Here is a link to a website that sells a on/off valve kit, kinda shows you where to start inspecting.
http://www.fullwavemarine.com/roostertailkit.html