[nymart]

I have a 2005 Yamaha F150 on my 191FS. I used to run around 32-24 MPH at WOT and 5000 RPM. The RPM and MPH started dropping last week and I found that my fuel filter was really nasty so I replaced it. I also changed from the stock 19" pitch prop to a 15" as I was hoping for a better hole shot. I tried it this weekend and I do have a better hole shot but instead of my RPM going up as expected, I am maxed out at 4000 RPM and only getting up to 24-26 MPH. Any suggestions as to what might be causing my lack of power?