I just purchased a pontoon with a 2001 mercury 115 efi 4 stroke. When talking to the previous owner he stated that when he would take the boat out it would only hit 4200 rpm, but if he tapped on the fuel rail it would hit 5500 rpm. He said he took it local dealer and they said they fixed it. Boat Sat for 2 years and he never went back out in it. This weekend I took it out and it done the same thing, so I tapped on fuel rail and noticed a big difference in power and reached 5500 rpms. He said he ran non ethanol fuel in it and I done the same and added 2 cans of seafoam. I'm guessing maybe an injector is clogged. I've read about taking fuel filter off and changing it and before installing new 1 fill it with seafoam. Does anyone have any other ideas? Thanks for any help.