2005 suzuki df 140 loses power after 5 hours rinning

[Megofish]

My 2005 suzuki df 140 4 stroke loses power after running for about 5 hours. I fish offshore and after 5 hours when I try to put any throttle on I can only go about 10mph at around 3200rpm. It runs great up until about 5 hours into my trip.

If I stop the motor for a few minutes then restart I can go to for example full throttle for a few minutes then rpm goes down to 3200rpm. The engine never dies just no power. Replaced all filters except hp filter, and the collapsed fuel lines that was damaged by ethanol fuel.

 

[99yam40]

what are the fuel pressures doing when this happens?

 

[Megofish]

I don't know since the only time I can produce the ptoblem is after being on the water for at least 5 hours. Is there a way to get pressure while underway?

 

[Megofish]

Do you think it is s problem with the Rev limiter?

 

[Megofish]

The primer bulb is firm when the motor loses power.