25hp 4 stroke no power

[Prostar197]

Have a 25 hp Yamaha 4 stroke on pontoon. Will idle and run 3000 rpm all day.
If you run rpm's up to 4000-4300 it will cut out and almost die after running for less than a minute. I have cleaned fuel filter three times, and have found nothing in filter.

[boscoe99]

Pump the primer ball continuously as the motor approaches 4000 RPM and see if the problem remains or goes away.

If it remains come back. If it goes away replace/repair the fuel pump.

[Prostar197]

tried your suggestion, pumping primer bulb may no difference.