Yamaha Outboards 250HP | F250UCB. Meet Yamaha’s award-winning V6 4.2-liter outboards. Fusing power, efficiency, speed and light weight, their intelligent design absolutely sets the standard for offshore performance. And now, you can add versatility to that list. A V6 4.2L model you can step up your power, without rebooting your rigging. Seventeen percent more fuel efficient at cruise RPM, up to 73 pounds lighter than some competitors and more than 10 years of proven Yamaha reliability.