Last fall I purchased a boat with a 1999 Mercury 225 EFI. When I took it out it went around 70 miles per hour and turned almost 6000 RPMs. Recently however, I have experienced some problems with the top end. Now it will only get up to about 64 and spin at 5400 RPMs. When I first experienced this problem, the boat would reach top speed, then it would loose power. Now it will not get to top speed at all. The motor preforms fine while accelerating, but at a certain point I can feel the power decrease as I am accelerating. The motor sounds fine when this happens, it just looses power. The compression is around 95 psi, and the spark looked good in all cylinders. I was thinking it is a fuel problem. I checked and cleaned the fuel filter on the fuel pump, along with replacing the water separator fuel filter. The filters did not look to dirty though and this did not fix the problem. Any help would be appreciated.
