Prop Question

[Blue_Runner]

My buddy just bought a 22ft Clearwater center console with a 150hp Yamaha 4-stroke. Its a heavy boat and comes with a "stainless" 19 pitch prop. Sluggish out of the hole and you have to ease the throttle up or it will bust out. Top end with the 19 p prop and light load is about 41 ish.

Here's one of my questions. The prop is said to be stainless, however it is painted black and a magnet will stick to it....so is it really stainless?

Another question, 2-stroke vs. 4-stroke - are the props interchangeable? The reason I ask is my buddy wants to try a 17 pitch prop to see what it does to his holeshot and overall numbers so I was thinking we could put my prop on his to see how it does. I have a newer Yamaha 150 2-stroke.

Thanks!
Blue