[THEFERMANATOR]

I went back and looked at your pictures, that is definately NOT a 25" leg. It's a 20" leg, you can tell by the lower engine mount spacing. And it looks to be a V4 lower unit, not the hybrid unit that used a V6 prop. Have you counted the prop shaft splines? Or roughly what is the outer diameter of the prop hub? If it is a V4 lower, it is pretty much certain to be a 2:1 ratio which is proper for that engine. The 1.86:1 ratio in the V6 lower would KILL the V4 looper by taking it out of it's power band vs prop speed. Your prop sizes also sound like a V4 lower. I still think you need to try a 15 or 13 pitch prop. My 140 slings a 17 pitch to 46 MPH at 6100 RPM's, and a 19 pitch to 53 MPH at 5600 RPM's. It would spin a 15 pitch to around 5800 at 34 MPH on my old boat, wich would have been close to a V20 in weight.

What is your current WOT and speed at that RPM?

If your reaching 28 at 4000 RPM's your tach is pretty much dead on. 4000 with a 15% prop slip comes out to 27.4MPH. Sounds like the engine may not be tuned properly, or there is something amidst in the engine itself. You say you have 120-130 pounds of compression, have you checked this against another guage. I'm running 150-155 pounds in my 140 with a .020 over bore.

And all of the electronics are the same from 120 to the 140, no differences in between the 2 up through the 90's. The differences were internal. The numbers stamped on the block where you say is a casting stamp as I believ mine is stamped 138 there. Even if it has some 120 parts, it don't make a big difference. Both of them are torque monsters very well suited to a v I think. The problem being is these engines don't make much power up until around 3500 RPM's. If your overpropped and not letting the engine hit it's peak, it will be WAY off on RPM's. These engines are rated @5600 RPM's.