When you mash the gas does the boat rev up and just not go anywhere? Are you hearing any funny noises from the jet pump? If you can get to the hand hole clean out on the pump open it up and take a look in there and make sure nothing got sucked up. NOTE: if your handhole clean out is inside your boat do this while on the trailer. Also crawl under the trailer and take a look up into the intake and again make sure there isn't something sucked up in there. Does your boat have a droop snoot on it? If so your pump may be air locked, if that is the case make sure that the reverse bucket is open when you back the boat into the water so it fills up with water and pushes the air out.