Ruff up that Yamaha grey with some 120 grit, make sure to remove all stickers first, make sure your original clear coat is removed in the sanding process, wipe down with acetone twice, mask grease zirks and pivoting parts ie swivel tube areas, water intake grate, greased areas, and finally paint with PARKER DUCK BOAT PAINT.
I shoot mine through a cheap Wagner electric paint gun. Thin the paint about 15-20% before spraying. Make sure you do TWO coats of your base color and then stencil accordingly.
IMO, cardboard stencils work well, but are messy and expensive if you paint a large surface area and want to get it stenciled fast. I prefer to cut Palm Tree frawns. They are free, readily available, and when they load up with paint, throw them away.
Here's my 70 Johnson after a hard 2013-14 season