2013 mercury 40hp 4 stroke efi won’t run at full throttle

[Riverbottom]

motor idles fine at the ramp but bogs down and sputters after about 100 yards. If I stay at a higher throttle it will rev up and back down until it chokes itself out but if I drop back to neutral it runs rough and sometimes shuts off. fires back up no problem and will take off for a few seconds then does the same thing. runs good at quarter throttle or less. Replaced fuel line, bulb, and filter. some days it will only do this once or twice then it straightens out. When it cuts off I take the bulb and put as much pressure on it as possible and it seems to make it a little farther. any help would be greatly appreciated. I'm thinking fuel pump but I'm no mechanic by any means.

[EuropeanAM]

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