I am currently running a 26p SS prop on my 1996 Nitro 170tf bass boat with '96 Force 120hp engine on it. My RPMs are running lower and it doesn't seem as fast as it used to. It used to run 5250RPMs+ It would even start to chine
walk(?) I got it so fast. I I have not changed props. RPMs are around 4200 running in the water. I took it to the shop and they said it is running the correct RPMs on their dynamo (4750-5250). Or course that does not take into account the prop. They said the 26p is too much and to go down to a 21-23p. Does that sound about right?
Or course perhaps my tach was off. But why would it running at much lower RPMs with the same prop? I am taking it out tonight to try it again.
The boat weighs 1229lbs dry, plus 3 batteries in the back. Not much weight in the front.
I mentioned the throttle cable to them but they said it was adjusted right. I just had them link and sync it. The throttle cable does have a point where you can push it forward some more, but the speed does not increase any more. Like a little extra "slack" or something.
When the shop measured it on their machine it is reading the correct RPM range so they believe it is the prop. Maybe someone with experience with a similar sized boat and engine can tell what pitches they were running.