Prop recommendation

[BIP Bassr]

I have a 1989 Astro Quickfire FS18 Fish n' ski. The motor is a 1984 Evinrude 150 HP. No jack plate, prop to pad is 7-1/2". I had the aluminum prop that came on the used motor when I bought it. Not sure what type of boat this motor was on before I bought it. The aluminum prop was a OMC 14.5 X 19. I hit a rock loading it on the trailer and it took a couple small chunks out of it. I bought a SS replacement in the same diameter and pitch. It's also a standard OMC three blade 14.5 X 19. With the aluminum prop I was able to run about 43 MPH. No idea what the water pressure is. No water pressure gauge. I realize the motor is too low but I don't want to install a jack plate at this time. The boat comes out of the hole really well. When I switched from the aluminum to the SS prop my speed went up from 43 MPH to about 48 MPH. This is on flat water. Boat still hole shots well. My RPM was about 5500 at WOT with the aluminum and dropped to about 5400 with the SS. I was looking at a 14.5 X 22 Raker and was wondering if I would pick up any MPH or if I'm where I need to be with the 19 pitch prop and the RPM I'm running. I know getting the motor up out of the water would get me speed but I don't want to do a jack plate at this point.

[jc2bg]

It’s been a long, long time since I ran a rig like yours, but if you’re running 5400 rpms with a 19 pitch, you’ll probably be below 5000 rpms with a 22 pitch, especially since the Raker is a more strongly cupped prop than the standard OMC 3-blade. Almost certainly you will run slower, not faster, unless there’s something drastically wrong with your current prop. And hole shot will probably suffer a lot as well. It shouldn’t take a jack plate to get the engine higher. Unless something weird is going on with the engine attachment, just raise it a hole or two.

[BIP Bassr]

Thanks for the feedback JC. Yeah, it's a bit of a blast from the past. The boat runs and floats and I don't have a lot in it so I should probably just leave it as is. I'll look at raising it up on the transom.