Thanks. There's a prop with the thrust washer, etc. on the boat now. And yes, this prop came off of a Mercury 150. I'll give it a go this weekend and see how it works.
That prop has (square) ports just below the leading edge of the blades....just below as the blade turns. This allows exhaust gasses to flow over the blades reducing the density of the water, reducing the load on the engine and allowing faster rpm buildup. They are used on heavy sterned boats, aka bassboats for faster hole shots...planing out of a standstill.
What you will find on going from a idle to firewalled throttle is that the engine rpms will immediately jump up to some intermediate number determined by your particular situation..rig, load, trim setting, environment and all. If the holes are sized correctly for your boat, you will have a much faster hole shot....change from sitting in the water to running on the water. If too small you won't notice them....they aren't too small......if too large your rpms will be excessive delaying your hole shot completion.
Once you get up to some reasonable speed, say 20-25 mph, the water pressure flowing past the prop barrel will seal off the holes and you won't know they're there. Really what it does for you is give you a dual pitched prop....shallow pitch for hole shot and high pitch for WOT joy riding.
Some folks recommend that you don't use them on I/Os. Mercury/Quicksilver makes rubber plugs to fit that prop and you can get a blank if you don't want any shot enhancement. They're solid rubber. Try it and come back with how it went. I am interested, for one, on how it went for you.
