I own a 2002 Yahama 200 OX66 Saltwater Series it on a 2170 Blazer Bay. I also have a 6" manual jack plate. I'm running a 23 yahama pro series prop. Running in fresh water, summer time, full tank of gas med. load I could turn 5.9k rpms. My problem started about a month ago running almost full throttle 5500 rpms the motor backed down to 5000 rpm without any throttle movement. Even with increased throttle the engine wouldn't run over 5K. Through out the day this same phenomenon would happen but not every time. I thought it may have been fuel starved so I changed the fuel filter and the plugs. This solved the problem for one trip but it's back again. Any sugestions on where to look?