yamaha o/b running bad

[richardgp]

I start it at my dock, it runs perfectly, then I go about a mile at fast idle, to a go fast zone.
I then trottle up to try to plane off and the engine just sputters an falls on it face..
It will not go any faster, just sputters untill I trottle back then it runs great at about 1100 rpms or so.
Then I turn off key and it a couple fo secomds restart the engine , put it in gear , hit the trottle very hard and the boat jumps up and runs up to 30 mph ao so like it should . I then run between 20 and 30 mph it runs fine.
If I the bring it to an itle and hammer it again it usually runs up to top end with very little surge.
I have a 2004 yamaha 115 four stroke o/b. on a 19 ft center console Key West.
Whats the problem ?

 

[99yam40]

Monitoring fuel pressures while this happens might give you a direction to follow

 

[Capt Ken]

Getting about time for the lift pump to start failing. Listen to the pump while the engine is idling. If you hear it tapping then it's going out.

 

[richardgp]

Still doing it.............

 

[99yam40]

If you are not going to test anything,
take it to some one that can and will

 

[richardgp]

36 lbs fuel pressure, had a computer readout that said nothing wrong...
changed fuel filters, and squeeze bulb. ????????????????

 

[99yam40]

Was this done while problem is there?
If not checking things while running fine does not mean anything

 

[richardgp]

I thought that the computer readout listed problem codes ?
There was a problem that said too cold or something to that effect. So I
purchased a thermostat. Now I need to find the place to install it.
I must be blind but do no see it ???
I find videos on utube, but not one for this engine.

rgp

 

[richardgp]

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