Help! 96 nautique with GT-40 bogs out of hole and lacks top end speed

[ScottStewart]

Hi, new to the site and unfortunately have a problem with my 96 ski nautique, hoping someone has experienced this issue and can help. Initially, while running at ski speed the boat would hesitate, slow down, then recover. Then it started doing something a bit different, fairly strong out of the hole, get up to speed at ok rate then take off suddenly(engine running strong) so I have to back off on throttle. NOW it is sluggish out of the hole, and won't get up over 36mph (4500rpm) at full throttle. I picked up a fuel pump relay switch and new fuel filter but have yet to try the boat. Any tips or fixes would be greatly appreciated

[Chexi]

Disconnect battery after installing the new relay. Wait a few minutes, then reconnect to reset the ECM.

[DanielC]

Do this.
http://www.planetnautique.com/vb3/sh...=fuel+pressure
Make sure you are checking the fuel pressure when you are experiencing the hesitation, or bog.

[ScottStewart]

Ok, thanks guys, I am heading out to the lake today to give things a try.

[ScottStewart]

I replaced both relays and the fuel filter, and put a pressure guage on the fuel rail, it read 42psi. ran the boat at full throttle and it still read 42psi. Thinking i had solved the issue I skied behind the boat, it seemed fine but on the second pull it was again sluggish out of the hole so I dropped off the wife and kids and went for a rip myself. Could only get boat to 37mph again, but on second attempt from a stop to full throttle around 34mph it took off...felt way stonger and ran up to 41mph. This happened on 3 more attempts, its like it just catches and goes....the issue remains. The previous owner felt he had electrical issues in the past and had disconnected his stereo, pulled the heater, and perfect pass, I'm not sure if this is the same reason. HELP!!!!! Thanks

[DanielC]

What is the fuel pressure when the engine is acting up?

Yes, that means you may have to have the fuel pressure gauge hooked up when you are driving the boat. Make absolutely sure there are no fuel leaks.

[rickmustang]

Fuel Flow

Sounds like an issue with fuel delivery. Easy to change fuel filter, but tanks have been known to have trash in them. There is a screen at the bottom of the plastic pick up in the tank. I just cleared mine by blowing into it and fuel then flowed freely.

[swooddc]

sounds like trash in the pick-up to me. got to check the fuel pressure though to be sure. mine was doing something similar and I had a piece of plastic shaving stuck in the fuel pick-up. would snap closed like a flap at high rpms, it would idle and run fine at low rpms. had a devil of a time getting it to act up with the pressure gauge on. finally pulled the pick-up and found the trash.

[ScottStewart]

thank you guys! I will put the pressure guage back on and have a look again, and will absolutely check the fuel pick up. Off to the lake again to giv'r another try.....

[ScottStewart]

Thanks everyone, especially swooddc!!!!!!!!!!!!!! It was the fuel pickup screen, half full of crud. I cleaned it out and took the boat for a rip. She is running like a rocket now! Super happy....and very thankful I don't have to haul the boat somewhere for service and lose more of our very short summer....back to worry free skiing again.

[ScottStewart]

Unfortunately my boat woes continue. She ran strong for a day, then went back to bogging out of the hole, and not getting over 36mph. I checked the screen at the pump again (clean), cleaned the screen at the 90 entering the fuel tank (not much debris there). I couldn't unthread the dip leg into the tank so I blew air into the tank and it seemed to be clear. Also blew out all fuel lines up to the end of the fuel rails. Just for the **** of it I used throttle body cleaner as well. After putting everything together the boat wouldn't get over 25mph and ran like crap...I re-checked the fuel pressure and it was about 15psi. Any suggestions would be great...I also have a question...I thought the engine only had one fuel pump which was between the fuel tank and the fuel filter, can someone describe where the other one is. I have removed the fuel pump assuming I need to replace it. Once again any help would be greatly appreciated!

[lajhal]

Unfortunately my boat woes continue. She ran strong for a day, then went back to bogging out of the hole, and not getting over 36mph. I checked the screen at the pump again (clean), cleaned the screen at the 90 entering the fuel tank (not much debris there). I couldn't unthread the dip leg into the tank so I blew air into the tank and it seemed to be clear. Also blew out all fuel lines up to the end of the fuel rails. Just for the **** of it I used throttle body cleaner as well. After putting everything together the boat wouldn't get over 25mph and ran like crap...I re-checked the fuel pressure and it was about 15psi. Any suggestions would be great...I also have a question...I thought the engine only had one fuel pump which was between the fuel tank and the fuel filter, can someone describe where the other one is. I have removed the fuel pump assuming I need to replace it. Once again any help would be greatly appreciated!

There are two fuel pumps a low pressure and a high pressure pump. The low pressure is the first one coming from the tank, than the second rest inside of the fuel filter. Check that out, it could be your problem.

[bradb]

I've been fighting the same symptoms on my '94 nautique with TBI. After checking fuel pressure, timing plugs, filter and fuel pickup screen, etc my dealer suggested I try replacing the coil packs.
I had a spare one from troubleshooting ignition probs a few years ago so I swapped out one pack and it still ran poorly. I swapped the other out and it has ran fine since (5 days out on the water) so I'm cautiously optimistic that I have it figured out.
Don't know if you know anyone with the same model boat or have a dealer nearby that will let you borrow one to try, but it might be worth trying? It only takes 2 min to swap and rule it out as a possibility.
Good luck,
Brad

[H2O]

There is a fuel hose connected to the high pressure fuel pump (inside the FCC) that is known to crack. Remove the fuel filter from the FCC to expose the high pressure pump and carefully check this hose.