Hi,
In a 2-stroke, a little extra oil in the fuel protects the piston skirts. In a 4 stroke... it doesn't need it since the oil for pistons (and all the other parts) comes from the sump. Also... if you run oil in the fuel of an injected 4 stroke... it could mess up the injection system.
I wouldn't do it.
If it were my new boat... go out by yourself for a few minutes, and let the engine warm up. Then mash the throttle wide open for 5 to 10 seconds then close it to an idle, and sit for a minute or so. Then, repeat. After that, go the the shore, turn off the engine... load up the boat with your gear, and take it easy for the rest of the day. Once back home... I would change the oil. After that... enjoy the boat as normal.
Some people like to break in an engine easy. I like a few hard accelerations, and decelerations to seat the rings for a better seal. (better seal gives a longer engine life, and more power) But, you don't want to hammer on the new engine all day. The rest of the moving parts need to seat... and things like the cams need to "Work Harden."
My 2 cents... take it for what it's worth.
