97 Sport Nautique Looses power after an hour of use

[BobinIL]

I am pretty sure I have another fuel issue. I have been out twice with my 97 sport GT40 after the fuel injector issue. to recap It was loading up at idle so I have replaced the high and low fuel pump, all 8 fuel injectors, the fuel pressure regulator the plugs, wires, dist cap and rotor. drained the old gas and refilled it with fresh gas. now I run it for about an hour of wakeboarding and it cuts out at higher speeds. drop back down to idle and it will run fine. I put the fuel pressure gauge on it today and we boarded until it started acting up and saw the fuel pressure drop to 10-15 psi let it idle and the pressure comes back up to normal and it idles fine. take off and in about a minute is starts cutting out again and looses pressure. here is what I think is going on.

could be some debris in the fuel tank plugging up the fuel screen in the tank
could be the low pressure pump I just put on is bad.
could be a plugged fuel filter in the fuel cell.

any ideas on how to clean out the inside of the fuel tank??

any other help would be greatly appreciated.

[The Hamster]

Im currently having a very similar issue. I also replaced the Low Pressure fuel pump thinking that was probably the problem, and i replaced the fuel filter in the FCC. Did you ever figure this issue out? If so can you please advise what it was?

[BobinIL]

I am going to replace the anti siphon valve on top of the fuel tank. I had 2 others respond to me on another forum stating this could be the problem.

[The Hamster]

Have you removed the screen / tube from the tank yet? If so how did you do it? Im a little afraid of removing mine to inspect / clean because i dont want to accidently destroy Any threads or anything. And is the anti siphon valve the brass fitting that is threaded on one end and barbed on the other? I believe we are having the same issue. If i some how figure this out before you do ill advise what the fix was. Please do the same. Im at my wits end here.

[The Hamster]

I just removed the anti siphon valve and learned there is a screen at the end that threads into the 90 degree fitting on top of the tank.Mine was completly clogged with gunk. Hard to believe this didnt impeed fuel flow. Im pretty confident that was my problem. I will lake test in the morning and ill let you know if its fixed.

[The Hamster]

I took the boat to the lake this morning after we cleaned the screen in the anti siphon valve. The boat had ZERO issues and ran awesome. When you take the anti siphon valve off be sure to check / clean the screen. That was my problem.

[BobinIL]

Yes that was my issue too. The screen was in the pickup tube and it was clogged with a bunch of gunk. Picked it out with a small screw driver then blew air through it from the opposite end. It came out in a big clump looked like a dust bunny

[Aaren22]

How did you clean the screen out?

[mpost]

BobinIL,
I cant tell from your picture, is that pickup tube flexible or a pipe? can you get it out of the tank without pulling the tank???

[BobinIL]

Yes it is plastic flexible. Take the fuel line off, unscrew the anti siphon valve then you can unscrew the elbow out of the tank then you have to work it out bending it and pulling it to get it to come out.

[Neptune442]

Must be something in the water....because I just finished diagnosing similar symptoms that both you and The Hamster had in my newly acquired 2000 Sport Nautique with the GT40. Mine ended up being caused by 19 years worth of crud built up in the low pressure fuel pump. A new fuel pump has her running like a Swiss watch. But of course it didn't stop there. Installed an inline fuel filter between the tank and the pump to hopefully help prevent this in the future. I then decided to remove the fuel sending unit so I could peek down into the tank...big mistake....just an absolute filthy disaster. There was even some nuts, bolts, and an old gas cap chain down there. There's no way I could adequately clean the tank out without removing it, and with how picky I am...there's no way I could sleep at night knowing the tank looked like that. So out she went (what a job!) It all turned out good in the end though...because now after some power washing, my boat is probably the cleanest its been since it left the dealership. And I can sleep easy knowing that I have a squeaky clean fuel tank and system.

[Neptune442]

Oops, doubled up on the photos....dangit

[mpost]

Neptune442
Nice job on cl3eaning that carpet. Had mine out this winter and could not get that carpet clean. Was in my shop and could not use a pleasure washer since it was 0 outside
How do you like the Y pipe on your exhaust. Is it much louder than it was with the muffler???

[Neptune442]

Neptune442
Nice job on cl3eaning that carpet. Had mine out this winter and could not get that carpet clean. Was in my shop and could not use a pleasure washer since it was 0 outside
How do you like the Y pipe on your exhaust. Is it much louder than it was with the muffler???

You know, I can't completely speak to how much of a sound difference the new exhaust set-up has made, because I noticed the gaping hole in the hull hugger muffler during my initial water test after purchasing the boat. So I didn't drive it much with the hull hugger..but really I can't tell much of a difference. It sounds very nice, not obnoxious at all. I went the Y-pipe route both to simplify things, and because I got the Y and the new exhaust hose for about half the price of a new hugger. I didn't feel like repairing it because it was obvious someone tried to repair it in the past.

[Tryathlete]

I am pretty sure I have another fuel issue. I have been out twice with my 97 sport GT40 after the fuel injector issue. to recap It was loading up at idle so I have replaced the high and low fuel pump, all 8 fuel injectors, the fuel pressure regulator the plugs, wires, dist cap and rotor. drained the old gas and refilled it with fresh gas. now I run it for about an hour of wakeboarding and it cuts out at higher speeds. drop back down to idle and it will run fine. I put the fuel pressure gauge on it today and we boarded until it started acting up and saw the fuel pressure drop to 10-15 psi let it idle and the pressure comes back up to normal and it idles fine. take off and in about a minute is starts cutting out again and looses pressure. here is what I think is going on.

could be some debris in the fuel tank plugging up the fuel screen in the tank
could be the low pressure pump I just put on is bad.
could be a plugged fuel filter in the fuel cell.

any ideas on how to clean out the inside of the fuel tank??

any other help would be greatly appreciated.

Quinner had the answer on CCF. I see it was your anti-siphon valve/screen/fuel line. You might want to post this on the CCF site


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