1999 Nautique gt-40 dying mid pass

[slow]

Boat shuts down in the middle of a pass. Perfect pass is working fine. Seems electrical. Boat turns over fine afterwards. Sometimes starts and other times won't. Wondering what I could check easily. Only thing I have tried is bypassing the kill switch, but that wasn't the problem. Any advise would be appreciated. Thanks

[Skihack]

Make sure antisiphon valve isn't stopped up for starters. It is on top of gas tank where fuel supply line is connected. Clean all the varnish from it. If that's not the problem, you're going to have start troubleshooting fuel supply and so on. Need more info though. It is running fine up to speed after it initially knocks off. It's not going into limp mode or anything is it? Also, Make sure the fuel filter in the separator is good and clean.

[BruceEmery]

My friends GT40 did this quite frequently. It was usually a clogged fuel cell (filter).

[slow]

I will look at both of those. I was thinking it was electrical, because boat, just shuts off. It has never sputtered or gone into limp mode. When I can get it to start it runs great without hesitation. Thanks

[slmskrs]

Post this on www.correctcraftfan.com in the engine repair of the forums section. Lots of CC specific help (especially for those of us with GT40 engines. Could be the fuel relay, the HP or LP pump, or any number of electrical items.

[slmskrs]

Oh, and I have yet to have my fuel filter in the FCC get plugged up; every time I've opened it to replace it, it looks clean (replace it anyway). I've had the screen mesh in the top of the tank get plugged up, a pin hole in the hose that the HP pump connects to in the FCC, and my LP pump get weak and need replacing. Others have seen the fuel pump relay go out. If you post on correctcraftfan.com, make sure you list as many symptoms, conditions when it happens, what you've checked so far, etc. Any difference with speed (slower, WOT, etc.)? When it cuts out, does it sputter or just die cold turkey (like turning off the key)? When it won't start, how long before it does?.....etc....

[A_B]

As soon as it dies, lift the motor box and turn the key to on, not start, and listen for the fuel pumps priming. That would be my FIRST step. The relays go out intermittently, and you could pull your hair out chasing anti-siphon valves, fuel filters, etc...

 

The relays are $12 parts, one is for the pumps and one is for the ECM, The pump relay has a green/yellow wire and that is one of the ways to tell which is which. The relays are identical, but you can't use the ECM relay in place of, as you need both to complete the electrical circuit. If one is bad, replace both.

 

Could even be a loose wire on the ignition switch, but check the relays first....

[ForrestGump]

Agree with AB. A quick thing to check is that the ECU plug is seated correctly and not loose. There's an 8mm bolt in the middle that screws it into the socket. Make sure that's not loose. Another thing it can be when it just dies completely like that is the TFI module in the distributor. It's the flat thing on the front of the distributor which the harness plugs into.

[slow]

Simskrs - It dies like the key is turned off. It turns over but will not start. It finally got to the point it wouldn't start at all. Didn't have the time to mess with it and took it in to the dealer. Hopefully they find the problem. I really like this 1999 nautique. Bought it new, but I am starting to have more little things go wrong each year. Thanks for all the advice. I will let you know that the problem is.

[McGruder]

Check your kill switch. You can bypass the kill switch to see if that is the problem. If the electrical connection is sporadic, the problem can come and go.

[ral]

Clogged fuel filter would do that. Has happened more than once to us in our 196 and 200. Fuel could be cleaner here...

[ToddF]

The TFI modules are notorious for going bad in fords. It is easy to replace. I used to keep a spare one with me.

And it will do exactly what you are describing. It should have been called a thin film module.

 

If that is what they find it is a simple 5-10 minute fix and hope they don't charge too much.

[walleye]

I had exact same sypmtoms 3 weeks ago on a 98 s/n. It was the 2 relays mounted @ the back of the motor. I ordered them from discount marine, about 12 bucks per.

[JackQ]

I had this happen to my boat a few years ago. There is a brass screen at the bottom of the fuel tank and it was clogged. When I was between passing enough fuel would get to the fuel cell (next to the engine) to run one maybe two passes, then would die mid course. Easy to check, unhook the fuel line at the fixture at the bottom of the tank, unscrew the fixture the screen is inside.