'97 Nautique randomly shutting down

[Seth C]

I have a '97 Ski Nautique 196 with a GT-40 EFI. Boat has perfect pass. Boat has ran great the last 6 years I have owned it until last summer. Boat would start up great, we would then run 4-5 passes and engine would either completely shut off or would cut in and out eventually shutting off. Once this happened, majority of the time it would start back up and maybe run for another couple passes then would shut off again. Sometimes we could limp it back to shore, other times had to be towed. At this point (maybe 20 minutes in), engine would start up normally then shut off within 1 second. One time we put boat in it did this right from away, it would start up normally but immediately shut off.

What we have done:
Always run Startron fuel stabilizer
Tested battery, parts store said it was strong
Re-built alternator
Tested starter and that is fine
Replaced both fuel pumps

Any thoughts on what is going on?? Help much appreciated!

[d_nodixon]

Electrical short?

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[nukemustang]

Fuel filters? Sounds like it's almost bordering on a "vapor lock" type condition. Plus it sounds like it's getting worse with time/age?


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[Tryathlete]

If you go on CC Fan site and search "Poor Man's GT40 troubleshooting guide, I believe you will be led to a few possible diagnoses, but since you've already replaced the fuel pumps, particularly the LPP, I'd look at the lanyard/kill switch, anti-siphon valve, and ignition switch.

I'd also do something a little strange just to see if it makes a difference.....when you start it, and it's dying right away, keep the ignition switch in the "start position" a short while longer after the engine kicks on to allow ECU to get a good PIP signal. It may feel strange doing so, but it helped me a few times when I went through exactly the same thing.


Sooner or later your toys own you

[EchoLodge]

Fuel Relays NAPA ECH AR174
Hella 4RD 960 388-31. Have you checked them?

PFC Team Green Boat

[shag]

It might be your ECM.... Where all your spark plug cables emit from .... Sounds classic. I have had two nautiques with that system and when it gets hot (and is failing) it causes those symptoms...

[DLafont]

+1 on checking the relays

[Tryathlete]

Take your time, be methodical, replace cheap stuff first, one change at a time, and definitely start with the Poor Man's GT-40 troubleshooting guide. Simple stuff....like an added in-line filter, the "kill switch" lanyard (which we should probably all bypass, since I've never seen anyone wear it anyways and it would make me feel like I'm on a wave runner).


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