Hi
I have twin 502 MAG MPIs with the original 3x3 props from 1998.
I haven’t posted before, so no pics allowed, but they are the 48-823665/6 combo, 24” pitch.
They have served me well for hundreds of hours, and I was considering reconditioning them vs buying new.
I understand that the 3x3 setup has been superseded by 4x3, with the front prop now a 4 blade.
Is there any advantage to this newer setup over my existing 3x3?
The boat is a 38’ Shelter Island runabout, 11k lbs displacement, WOT 50+ mph and WOT RPM are 4,600.
The only minor gripe I have is some cavitation during the hole shot, if the helmsman is too quick to put the throttle down, otherwise all is good. The cavitation has occurred since I got the boat 4 years ago.
thx,
eric

I wouldn't call the 4x3 superseding the 3x3, just another design by Merc. Came about the same time Hill Marine came out with their 4x4.

Being MPI your WOT rpm should be closer to 5200, so maybe going to 22P

Talk to Brett at Bblades, he did an amazing job with my B3's. got rid of cavitation that was so bad it was eating away at the blades, picked up 6 mph cruise speed.
Less expensive and better than new props.