MichaelW wrote:Q1: if I should get the 130-HP engine for its lighter weight, will it have enough horsepower [for slalom water skiing and wake boarding]?
Typically when changing to a four-stroke-power-cycle engine from a two-stroke-power-cycle engine of the same rated horsepower, unless the new engine has larger displacement than the original engine, the performance will probably suffer somewhat, particularly in the amount of power the new engine can produce under heavier loads when operating at lower engine speeds.
A classic two-stroke-power-cycle engine would typically have a wider power band, that is, it can develop significant horsepower at lower engine speed ranges, where a four-stroke-power-cycle engine of the same displacement will probably only be able to develop its rated horsepower output at near the maximum engine speed.
The difference will be particularly noticeable when the boat is to be accelerated from a standing start with a heavy load, such as when trying to pull-up a slalom water skier.
To overcome the lack of low-engine-speed power output with the new engine, you can fit the engine with a propeller of lower pitch. This will tend to reduce the maximum boat speed, but less pitch will improve acceleration. And for water skiing, I don't think you would need to reach a boat speed of more than 30-MPH, so a lower top speed for that use might be okay.