Re: Prop size??
It doesn't matter what the book says. Its how the engine performs with any prop and how that prop performs depends on many factors. Boat size, hull type, load being carried, etc. So there is no "standard". To pick a prop you need a baseline. That base line is established by determining wide open throttle RPM and maximum speed achieved with what your normal load will be. You need a tach and an accurate speedometer (or GPS) for this. Without either you have no way of determining if the prop is correct. Too little pitch and the engine over revs. Too much pitch and the engine lugs. Neither is good for engine logevity. If you don't want to go through this routine, some telltale signs of incorrect prop selection are as follows: If the engine struggles to get the boat on plane, you likely have a prop with too much pitch. The engine will likely also sound like its laboring at any speed. On the other hand, if the boat pops on plane quickly but the engine sounds like its really reving higher than it should you likely have a prop with too little pitch. Any changes either way will be a "guess" at best since you have no baseline.
