I have a 2000' mercury 225 EFI. Here is what it's doing. It will start and idle just fine , rev up as high as I want it to go in neutral. Once I put it in gear , it struggles to plain off like it's starving for fuel. Once it does get up , about a minute later , it has very low power under 3000 rpm and once I take it over 3000 rpm it dies and just a few seconds later it will start back up , back under 3000 rpm . I have recently rebuilt the fuel pump , replaced the fuel filter and the spark plugs. I am lost as to what is going on. And the fuel pump was the " gravity fed " fuel pump. Not the electric fuel pump. I'm sorry if I don't know the correct term guys.