Your new Yamaha outboard requires you to operate your outboard for 10-hours "under load." This means that, to break in your boat's new engine properly, you have to have the outboard on the boat and you have to go boating. These 10 hours are the most important hours of the engine's life. When undertaken with a determination to ensure your outboard's long and happy maritime career, boating through the break-in process is a small sacrifice.
Step 1
Limit the throttle setting to about half-throttle for the first hour. Watch the tachometer -- the optimum speed for the first hour is 2,000 rpm during the first hour.
Step 2
Hold the engine speed to 3,000 rpm during the second hour of operation. This means you shouldn't go faster than about 3/4-throttle, rather than wide-open throttle during the second hour of your 10-hour break-in process.
Step 3
Restrain yourself during the next eight hours of boating -- you may operate at WOT for only five minutes at a time. After those eight hours, though, you may operate as you desire, since you have broken in your Yamaha outboard properly.