1998 Sea Doo XP 951

OK I just bought a 1998 Sea Doo XP with the 951cc engine. I am having a problem with blowing holes in the rubber exhaust boots connecting the expansion pipe to the rear pipe. This has happened twice now within 3 hours of riding. When I bought the ski the rave valves were disconnected from the solenoid. I reconnected them and since then this has been a problem. I noticed that the adjustment screw has been set all the way down. I don't know if that is the correct setting for this ski, I always thought they needed to be set flush with the top of the valve. Could this be my problem? I still have to check and see if water is flowing through the pipe the right way, but I thought I would ask about the rave valves. Any input would be great.