Hello, I have a 98 GTX rfi with the 787 engine. It runs great except my max rpms are around 6100 while in the water. I have checked and cleaned my raves and recrifier and fuel pressure etc. Reading old posts some people have had a similar problem and it turned out the water pressure regulator never slowed the water pressure to the tuned pipe, so I decided to pull it off and have a look. Everything was in good shape, a little black around the bottom of the valve seat, but it wiped right off. I tested the seat and it works perfectly. I was surprised how stiff the spring was and was surprised the pressure from the exhaust could compress it. So i started the ski with the regulator off and held my finger over the hole in the water box and was very surprised there was almost no pressure at all. So I guess my question is, is it actually the increased water pressure that compresses the valve? I checked and I don't have any exhaust leaks, so I am not losing pressure there. The ski was out of the water and the hose was not connected so there was no water going to the pipe, but I don't think that would create much more exhaust pressure.