Motor Just Dies under load.

[Us4parrs]

Looing for some input. Took the boat out today, everything went great for the first 30 min or so. I was running they family and nephew around the lake @ WOT and the motor just quit. Like fuel supply was cut off. Got it fired right up and took off again, Got to about 3000 rpms and ran it there for a short time and it Dies again. At times it seemed like electrical, It would just shut down like the key was turned off, but then I felt a slight hesitation here and there and shortly after feeling that it would die again. Most of the time it started right up, but once I had to open the throttle to get it started again.and once it started it idled fine. So that makes me think its fuel related. Its a 430A 4.3l. I put a new fuel pump in this spring so that shouldn't be the issue. Im going to replace plugs, cap, rotor, coil and all fuel lines to see if this helps. Any idea what could cause this sudden shut down would be great help. Thank you

 

[skydiveD30571]

When you have intermittent dying after a good long run like you had, the first thing I'd do is check the fuel tank vent. Unscrew the cap where you add fuel to your boat and drive around with it off.

If the fuel tank vent becomes clogged the vacuum prevents the fuel pump from sucking up fuel from the tank, and this usually presents itself as normal running while the fuel in the lines/carb is used up, then a sudden shutdown with running problems afterwards.

 

[Us4parrs]

Thanks for the reply I did check the vent and it is open and clear, I was talking with a few guys at work today and the subject came up about Fuel lines breaking down and the liners inside collapsing under a load. Plan to replace fuel lines today and hope that's the fix. Really hoping to finally be running the boat this weekend. Work has been putting a stop to my fun lately.
Would appreciate any other info or ideas. Not much time left before the weekend

Thank you

 

[Sparkinator]

My boat was doing something similar, and my anti-siphon valve had a wad of fiberglass in it. It was on the tank (suction) side of the valve. I tore everything I could apart and did it twice before I found the cause.