Gsx 787 rpm not cranking high when in water

[tony bombardier]

Hi people,
My gsx 787 I can crank up to 7000-8000 rpm when on dry trailer . But when I took it down to the lake it’s not going to speed due to rpm only went to 2800 even though I had the throttle at max . Can someone tell me why? Is the fuel line plug or garburator got plug ? Thanks .

 

[Mraw]

First thing I would do is check compression. 150 is perfect, 130 is marginal, 120 you will need a new top end. There should be no more than a 10 psi difference between cylinders. If compression checks out replace all grey fuel lines, rebuild carburators with genuine mikuni parts including new needle and seat, replace fuel filter assembly, and replace fuel selector

 

[tony bombardier]

Ok thxx

 

[simy200]

Ok thxx

Hello Tony, I have exactly the same problème here with my 96 gtx 787 engine.
Did you finaly find the trouble?

 

[tony bombardier]

Hello Tony, I have exactly the same problème here with my 96 gtx 787 engine.
Did you finaly find the trouble?

no I don’t know. Will have to bring it in to the service guy

 

[POPPS]

You could also pull off the rav valves and have a look for scoring on the piston.
Low compression and scoring on the piston often come hand in hand.