RE: 120 4 stroke prop ??
I have tried the 16-4 W on my 120 and it doesnt pull out quite as well as the 16-6 APC IMO . a 4 pitch is great for a 2 stroke or a small 4 stroke but I feel the 6 pitch is better for the larger 4 strokes. If properly propped for thrust they should not be turning over 9500 rpm anyway