engine hesitation on GT-40

[knorman157]

I have a 98 ski nautique with a fuel injected gt-40, and ive replaced all spark plugs and wires, distributor cap and rotor, high pressure fuel pump and new fuel filter for FCC also that little fuel line connecting the high pressure fuel pump to top of the FCC going to fuel rails, cleaned all fuel lines and tanks, replaced all battery terminals and connectors, cleaned flame resistor.
The issue im have is that only 15-20 min after the boats has been running it starts to hesitate drastically when running below 3000rpm as long as you dump the throttle from the start and you can get it to 3000rpm NO issue anything below she goes to ****.
when the engine is cold you would never know there is a problem then it just comes outta no where, it feels and seems electrical, like once the engine compartments and all connectors start to get warm its like something isnt communicating with ECM properly, and also during these problems im have fuel pressure sustains 39 +/-3 psi

[charlesml3]

Kinda sounds like a failing ignition coil to me. That's how a coil will behave. It'll work great when it's cold and as soon as it warms up, it'll start to break down.

-Charles

[knorman157]

HMMM OK.
Havent done that yet, your just talking about the coils running from the distributor cap to spark plug and if so
should i just buy a single ignition coil and once the issue starts to happen then one by one pull 1 wire from plug and same on cap and use single ignition coil

[knorman157]

also guy at nautique parts thinks it could be a oil pressure sensor or something im actually waiting on a calll back after he speaks to some team members he beleives its going into limp mode, but based on my actual symptoms im gonna pissed when i found out YOUR right
thanks Charles

[gun-driver]

Not sure why you would be pissed at the guy!!

He has not even seen your boat nor has he worked on your boat, he is just trying to help a guy out that knows nothing and is giving him "FREE" help. He could just sell you what you want and let you keep throwing parts at it until something sticks.

Maybe a "Thank You" for taking the time to check on this for me and calling me back during the busiest time of the season, would be better!!!

[beamons]

Not sure why you would be pissed at the guy!!

He has not even seen your boat nor has he worked on your boat, he is just trying to help a guy out that knows nothing and is giving him "FREE" help. He could just sell you what you want and let you keep throwing parts at it until something sticks.

Maybe a "Thank You" for taking the time to check on this for me and calling me back during the busiest time of the season, would be better!!!

I am guessing but I think he was being sarcastic.

[gun-driver]

I am guessing but I think he was being sarcastic.

Yea maybe you’re right, maybe I misunderstood

[knorman157]

No No im gonna be pissed at MYSELF when its as simple as a ignition coil that's literally the only tune up replacement part i havent done, im sorry for the mis understanding i should have re-read my post before posting it, im just at work and trying to be sneaky.

THANK YOU CHARLES FOR THE ADVICE HONESTLY
I DIDNT MEAN TO CONFUSE
HAVE A GREAT DAY
-KENNY NORMAN-IN VIRGINIA BEACH, VIRGINIA

[charlesml3]

I would think a failing oil pressure sensor would throw the Check Engine Light. I don't know for sure, but that would make sense to me.

Anyway, I just looked and even on NautiqueParts, the coil for than engine is only $45. You could take the one off you have and take it to most any auto parts store and likely get a Ford version for even less.

Anyway, I hope I don't lead you on a goose chase but I just replaced a coil on my neighbors boat with the same symptoms. Ran great cold. As soon as it warmed up, it would start skipping and sputtering.

Let us know what you find!

-Charles

[knorman157]

THANK YOU AGAIN CHARLES

I AGREE WITH YOU ON SWITCH
I forgot my neighbor has a program on his computer for the nautiques and we are going to plug it in and see what codes are throw then
clear the codes cause this has a been a 2 year battle hopefully coming to an end then once the problem happens again hopefuly it will identify the single problem charles i will let you know but i did check out my coils and im almost certain you are the ****ing man cause 2 of them not looking so good

thank you thank you for the simple but crucial advice i over looked

Thank You charles

[knorman157]

I fixed it!!!!!!!

So charles thank you for you help i changed the ignition coil and ignition module and the only thing that fixed was it starts now after motor turns over only once so that is cool but hesitation actually got worse haha
but i disconnected the oil pressure switch and water temp switch which are the 2 things alone that will throw the boat into limp mode intermittently and they actually dont throw an engine light they are there only to slow the motor down in event of lost oil pressure or if motor is getting to hot.

Boat runs perfect now and gages work perfectly just have to pay attention to them now

thanks again