2005 Johnson 150 2 stroke bogging at WOT

[Rylan12]

I have a 2005 johnson 150 that runs absolutely flawlessly at idle and jumps on plane and will pish the boat 50 mph no problem but as soon as you open it all the way up and hit around 55-57 mph it will start what seems like cutting in and out. If you let out of the gas a little it will run good again as long as you are not wide open. If you hold it wide open while it is doing it the motor dies out. Thought it may have been fuel pump so i put a new one on that didn’t fix it. Has brand new fuel line from tank to fuel pump. Please help!

 

[faztbullet]

VST may have leak or vapor pump diaphragm

 

[Billyfish24]

Usually vacuum leaks or restriction. Vapor separator is definitely a good place to start. Any leak at all will weaken fuel pressure. Also take off the carbs and check the intake screens on the throttle plates.