trouble Yamaha 250 HPDI 2004

Posted on high performance Yamaha forum but see that others are having similar problems with other Yamaha motors. My problem is when I put the throttle down hard and boat starts to plane, just before on plane it begins to cut in and out like it's not getting enough fuel. It cuts out one to five times before kicking in and once it's on plane it runs great. If I gradually work it on plane, no problem; only happens when I punch it, full throttle.

I've taken it to a mechanic who changed all filters, spark plugs and fuel line and ball. He seems to think I might have gotten some ethanol in there and that he saw some water and smelled alcohol. He recommeded to fill tank up with premium fuel and run tank through. Have half a tank left and it still does it. What I decided to try was to drain fuel tank and disconnected fuel line at the fuel filter and used the pump ball to try and fill a tank. Did not work, fuel would not flow after I pumped ball.

Any ideas or suggestions would be appreciated. Thanks.

That is odd. You should be able to pump ball and start a siphon. Are you saying when you pump the ball your getting no fuel or could not siphon?

Does the fuel flow while you are pumping the bulb or does it stops flowing when you quit pumping? Here are some possibilities to your problem. Fuel tank pick up tube screen clogged, fuel line has an air leak, LP fuel pumps leaking into crankcase, vst filter, fuel strainer, fuel pressure regulator screen, high pressure/compressor pump filters or clogged screens in fuel injectors. Sounds like fuel starvation during hard acceleration.

When I pump the ball, fuel comes out but when I stop pumping, the fuel stops. If I can't start the siphon, does this mean the problem might be in fuel tank area and not in engine? I disconnected fuel line from fuel filter and have tried to start siphon there. Thanks for the help.

In order for the fuel to siphon from main tank the end of the fuel line needs to be below the level of the fuel tank pick-up pipe. I’ve done this before to empty my tanks so it should siphon if there is no restriction in the fuel line.

If it does not siphon when the siphon hose is lower than the tank you may have a bad anti siphon valve in the tank. Could also be as simple as a plugged inline filter between the bulb and tank, air leak, restricted fuel line, or screen in the tank is a possibility as well.

did he plug it in
did he check VST pressure?
did he check for spark n all 6