GT40 Losing Power

[Housers99]

I just bought a used 99 Nautique with a GT40. When we first ran it things went fine, but it sort of crapped out on us a few times. The engine goes in and out, losing power. Afterward I can take off again and it runs fine. Assuming it was last year's gas, we ran it down and filled up with high octane, plus did a tune up with new plugs, plug wires, cap & rotor. Ran fine on two outings, but did it again yesterday. Seems like it is either not getting fuel or not getting power to the transmission. Not sure what to do since the problem isn't chronic. Probably calling the local shop on Monday. Any thoughts?

[Tony-M.]

I think that I would try changing the fuel filter

[Nautiqueman]

I just skiied with my buddy on Thursday that had replaced all the above items including fuel filter and the Nautique dealer looked it over. When the dealer checked it out, it would not mess up. So I will keep a lookout on troubleshooting for you. His 1999 GT40 has about 475 hours and has always been a pristine boat. I believe he even called PCM. It feels like it is running on 6 cylinders, but we skiied on it anyway. You could smell gas like it was not all burned when we were running the course.
You must not be the only one...

[Housers99]

Thanks guys. I dropped it off at the shop on Monday morning. Still waiting for a verdict but we are thinking fuel filter or pump. I'm still new to the boat so I'm not big on playing around with the fuel system. I figure I'll let them do it this time. I'll let you know the result.

[darrel409]

If you smell fuel,Dont turn the key. Run the blower and or open the cover. Pretty boats burn faster than ugly ones! Good luck

[Housers99]

Well the dealer checked it out and could not reproduce the problem. Fuel pumps checked out okay and fuel filter was changed. Mechanic said he can't find anything wrong. Took it out for a test run and had the same problem after 20 minutes. I am lost.

[Socbum]

Do you know how long it sat before you bought it?

I had the same problem on my old boat. It ended up having a bunch of stuff in the gas tank that would get sucked up in the pick ups and it would shut down after about 20 - 30 minutes of run time. After sitting for a 10 - 15 mins it would start up again.

Hope that helps.

[Housers99]

It may have sat a while. I just looked at the gas tank and it looks almost 1/3 full even though the gauge shows less than a quarter. Maybe this is related to the problem? I'll be talking to the mechanic tomorrow and running that by him.

[Socbum]

I just noticed you are in Columbus. Where do you take it for service?

[SprintCar39]

Housers99, James, Myself and Paul all looked at your boat last night. I was told that you ran the gas out of the tank and have since put new gas in it. Was that correct? We are thinking it is fuel related. The low volume fuel pump was checked and it looked fine. Paul went through about everything else. James has a couple of other ideas and will be confering with Paul this AM to help get you back on the water for the weekend. Eric

[SprintCar39]

Houser99, I see from one of your posts from above that you did replace the fuel...my bad. Your problem sounds just like what Nautiueman described in his post. The exhaust smells like fuel and it sounds like it is missing a cylinder. We noticed that while it was running at the shop. Still working on a solution.

[Socbum]

Houser99

You are in good hands with Paul and the Mid Ohio Nautiques team.

Sometimes it takes awhile to diagnose the problems.

Patience and boating go hand in hand.

[Housers99]

I spoke to Paul at Mid Ohio this morning. Thanks Eric for replying on the bulletin board as well. I think Paul wants to get it out on the water and see what it does so he can diagnose the problem. We may wind up replacing fuel pumps and some ignition relay components (starting to get outside my working knowledge of the engine there). I will be taking it on vacation for a week tomorrow. Fortunately my brother will have his Nautique there as well, so we won't miss out on any skiing. We'll see how it behaves and try to baby it a little. I'll turn it back over to Paul next week - I know I'm in good hands with the guys at Mid Ohio. Once they figure it out I'll be sure to post the outcome. Thanks again everyone.

[benwa43]

Check the rubber tube that connects to the high pressure fuel pump inside the cannister. The rubber piece on mine cracked and it made it run similar to yours and eventually it would not run at all.

[skinautique]

You don't have a "whistling" noise when you run the engine at any speed do you? If the boat has been exposed to gas with ethanol/alcohol, it could have caused one of the pumps to go bad and it would cause a whistling sound and would also starve the engine for fuel because it wasn't pumping enough fuel through.