I have a 02 Air Nautique with a PCM GT-40 351. My boat has 502 hrs on it. <BR>While underway at idle speed (2-4 mph) my boat just die's. It has never died when I am at speed or any other speed becides Idle.?????? <BR>Its like someone just flips a switch and it stop's. And when you try to re-start it the motor turns over and starts and then dies 1-2 seconds later Just like when you have the kill switch un-pluged. At first I thought my kill switch was bad so I cut the wires and soderd them together and the problem seemed to go away, (The kill switch wires are still soderd together and a solid connection) Its a intermitten problem, I cant predict when its going to do it. The only thing that seems to get it to re-started and sort of re-set is opening the engine cover for a sec and sort of airing it out then it will re-start and run for how ever long untill it decides to act up again. It might run all day long and never do it or it might do it another 2 times that day. Its never left me stranded but it is acting up more and more and I need to get it figured out. Any Ideas <BR><img src="http://www.wakeworld.com/MB/Discus/messages/65921/260240.jpg" alt="">

Are u sure it's opening the cover that temporaly solves the issue??? <BR>The only thing that happens when you do that is a exchange of fresh air, i dont know how it works in a fuel injected engine, but on carbureted ones it is important to keep good airflow on the engine in order for it to work properly. <BR>Why dont you try running it without the cover to see what happens??? <BR>In other case have you checked the fuel pump? <BR>or any dirt on injectors?? <BR>

So let me get this straight the boat dies, but then will not restart for a minute or so? If you crack the throttle open in neutral will it start right back up? That is testing to see if the IAC is cutting the motor or a possible lean run condition. Another question is going to be how does it die? Like someone shutting the key off or like a slow rich stall? Does it ever stall off idle? <BR> <BR>There are many variables that can cause this scenerio and things rarely get better but always tend to get worse, and will haunt you at the worst possible time. If there is a vacuum leak it can cause it to stall. The absolute best posssible way to check for leaks is with a smoke machine that most high end auto shops will have. If they don't they are cheap! You can try cleaning the throttle body out, but try to use a non caustic cleaner and keep it out of the electrical components. <BR> <BR>Scanning the computer might tell you something but the chances are there are no codes. The data stream can often be useful to see what caused it to die. Same with scoping it to see if it is an ignition cut caused by a bad sensor. <BR> <BR>You could always get the idle set up a little and disconnect the IAC and leave it there and see if it still dies. That will set a code for sure <img src="http://www.wakeworld.com/MB/Discus/clipart/proud.gif" border=0> Not sure if the factory scanner for boats can up the idle, like you can on many cars.

The boat will die like someone is turning a key off it dies quickley and clean. No studdering or trying to keep running just quits. I have tryed putting the boat in neutral and giving it some gas and all that does is make it harder to start. Its like it flud's it. Its like its a computer or some sensor because it will start No problem it runs for a second and then its like a computer or relay turns the motor off, Just like when you have the kill switch disconected. I dont know what it is about opening the motor cover that make it start but for some reason it works. The motor idles smooth and runs perfict. So I dont think its a vacume But ill check and look at all the hoses. Any other Idea's <BR>BTW: I have no idea what makes the motor start when you open the engine cover???

so, to state it clear, the motor does run perfectly while having the cover up???

Yes, But I wouldnt run it with the cover up for very long. Its like I would start it with the cover up and as soon as it would start then I would shut the cover and be on my way. <BR>BTW: the Temp gauge on the dash said my boat was running at 140 degrees. It didnt seem hot. When I would pop the engine cover It seemd normal operating temp so I dont think the gauge was off or anything

its vapor locking cant get enough oxygen into the intake the reason is doesnt do it at high speed its the high airflow

and when you open the cover u release the fumes and u get a fresh burst of oxygen even try making a couple of passes with the top popped and reclose it in the middle of a run

Aren't those boats covered by a 5 year warranty end to end? It does sound like a bad signal to the engine control module. It's prolly getting input from a bad sensor and shutting the engine down.

I agree with vapor lock but it has nothing to do with air flow into intake. Vapor lock refers to the boiling of the fuel in the rail thus taking the fuel away from the injectors. Check fuel pressure, If it dies again try cycling the key off and on a few times(leave it in each position for a few seconds) if this helps then it is a fuel problem. My boat died at idle for about 3 days on vacation then the pump quit. Opening throttle and it not makeing a difference should rule out the IAC motor. As far as i know this is not a sequential injection motor therefor there is no cam or crank sensor to go bad but ford had lots of problems with ingnition modules on these motors. I am not sure what kind of ingnition it has.do you have a spark tester?

Spoonman- Keyless ignition.

I agree with CAR. <BR> <BR>Had a buddy with a similar problem on a 04, check the keyless!

Could be many things. I would start with fuel filter, plugs, fuel pressure, voltage too low to run pump, etc. <BR>Good luck.

I was refering to the ignition system to ignite the fuel is it TFI like Ford automotive or something marine specific.

I am fairly sure the GT40 is MPI not TBI.

A friend had the same problem, was a result of a corroded relay terminal. <BR> <BR>(Message edited by socalwakepunk on October 17, 2005)

As far as I know the gt40 is an EFI engine. <BR> <BR>A friend had something like that happening too, but it never operated more than 2 secs under any condition, then he did what socalwakepunk said and it started working correctly

Jeff: what relay terminal did your friend replace. <BR> <BR>Vapor lock ????? the motor is running at 140 degrees and its not more than 80 degrees out When I open the engin cover its not any hotter than normal

Not sure which one, the dealer did the fix. I do know it was a common SPDT (Bosch?) relay on the main panel @ the motor. I would check, if it's O.K., use some contact cleaner, then replace all the relays (3 or 4). <BR> <BR>(Message edited by socalwakepunk on October 17, 2005)