97 Ski Nautique GT40 intermitted stalling, rough idle, not starting

[skiflyer45]

I searched but couldn't find this exact problem and would appreciate any input.

Intermitted issue with starting, stalling, and rough idle.

1: Starting issue: it will crank but not turn over. It sounds like the crank is somewhat weak when it happens like a weak battery. It happens when engine is hot or cold alike and at no specific time. It will start fine for days and then suddenly there is an issue for a few cranks. When it has the starting issue it seems electrical since the horn will be weak when pressed and appears to be low voltage (guessing). I will try it a few times and suddenly it will start on first crank like there was no issue. Other times I will give it throttle in neutral and that gets it started.

2: rough idle: Again, intermittently. Sometimes immediately after starting when I had the cranking/stalling issue other times stand alone problem. It will idle rough (600-850) for a few seconds then calm down and idle perfect. Usually sounds like it is about to stall as if starving for fuel (fuel pressure is good). There are a few times when it did stall. When the idle is very rough and I give it throttle it fixes the problem and the idle calms down.

3: Stalling: The stall has never happened under speed. Always during idle and again at no specific time (hot/cold engine). When it stalls it is usually accompanied by the rough idle or starting problem.

I have read relays might be a problem but it seems thats a host engine problem? Fuel pumps have both been replaced and pressure is good. Plugs are new. There is a 50amp circuit breaker that looks concerning (kinda rusty) but idk if that would cause these problems and its a $100 so kind of expensive to just trial and error.

Thanks in advance.

[whitecaps]

I'd replace both the relays(same relay but has two of them) with new ones, they are cheap and can be found at Napa if your Napa store is willing to match up. Or order from Skidim.com or nautiqueparts.com Second place to look is the small hose inside your FCC that can become cracked and cause similar problems.

[skiflyer45]

I have replaced both relays and don't know if it's fixed. I haven't been able to reproduce the stalling (which was rare anyways) or the crank without turning over.

However, the crappy crank has evolved into a click only from the back of the engine (starter solenoid) and no crank at all....intermittent again...sometime no issue starting whatsoever
.
When I hold the key in the start/crank position for a few seconds (3-10) it will eventually fire up (almost as if it wasn't getting power at starter). I tested the voltage at the solenoid, starter, ignition switch, and neutral safety switch and it appears to be good and working as it should during times when the boat starts and when the no crank happens. I removed the starter and bench tested it, it works fine. After re-installing the starter I have not been able to reproduce the problem but that means nothing...

Additionally I found a very corroded ground cables on my "house" battery (#2)..could this be related somehow even though its not a starting battery...

[Joshua J Rowe]

when you got the "click" and no crank you saw 12 volts at the starter solenoid?

[vanhanbr]

Wiring is a weak point on these boats, my horn never really worked until I rewired the dash. NautiqueJeff has a write-up on how to do it. #1 also sounds like a weak battery, #2 is a known issue on the ecm, new versions correct this, #3 could be the fcc needing a new filter.

House battery? That was not factory, depending on how it was wired, it could be draining starting battery. Go through all the wiring and clean any corrosion and coat with di-electric grease. Your alternator may be weak as well, if your battery is weak and alternator weak, it could also explain the rough idle. Also wouldn't hurt to buy a new starter solenoid (marine version.)

[skiflyer45]

Yes, that was 12 V at the solenoid and at the starter when it was just clicking ...
battery is not weak, 15 V plus

[vanhanbr]

For extra piece of mind, a new starter is $100.

[skiflyer45]

Where can I buy it for $100?

i don't know much about starters....are they known to have intermittent problems?

[Joshua J Rowe]

this "click" and no start issue is common.

i bought my boat last summer, it has always done this. it happens at least once every time i go out. usually takes 2-3 clicks and then fires right up.

I believe it is due to the starter solenoid either getting less power than it needs to make a good connection or the contacts inside it are dirty.

1 guy said his was fixed with a new ignition switch. Corrosion inside the switch being the culprit.

From what I have read I am leaning towards start circuit being the culprit. Corrosion here and there adding up to poor current/voltage to solenoid which in turn means solenoid makes weak connection to contacts for starter circuit and starter gets little to no current and cant turn.

The starter doesn't even try. No grunt at all when this happens.

[jrdowd]

I have a similar problem with the engine (GT40) dying randomly when hot. Just dies. Try and start it and no fuel is getting to the motor. Wait five minutes and it starts right up.
FCC filter has been replaced, gas is fresh. The boat is used frequently.

[JD ski]

I would start with the simple stuff that probably needs to be done any way. It could be an electrical issue but some of your description describes one of two issues, no fuel or no spark. So, get a fuel water separator additive (HEET) is the brand I get locally and it is cheap. Put in twice as much as directed. Run the boat and see if this helps. If this helps you may not be maintaining your fuel tank as needed and repeat the procedure. Then buy Chevron tecroline fuel injector additive and drive the boat. If this also helped, change the fuel filter and start using Sta-Bil marine or similar product in your fuel every time you add fuel.
If this is a fuel related issue this is what happens. With cold and heat fuel inside tanks will condensate. Always keep your tank full when sitting for any amount of time. When a tank is full there is less room for condensation. This condensation adds small amounts of water to your fuel tank. This happens with all fuel tanks. It usually only becomes noticeable as you describe above when a tank has some years on it such as being a 1997 and precautions have not been taken to keep the moisture at bay. Fuel tanks are something most people pay no attention to. In cold environments this is frequently the cause of even modern vehicles not running. The moisture freezes in the tank and or fuel lines and your car does not run. The guy I purchased my 1999 Air from kept the boat in great shape. But I had no idea of the condition inside the tank. So, with my first tank I did the above routine and always add Marine Sta-Bil with every fill up. It is cheap insurance for a good day on the lake.

[jrdowd]

Thanks for the tips. Last time it died I checked the FCC and it had pressure. I tried to start it and heard the fuel pump, but it would not start.
I noticed the temp gauge above 160. Let it sit until temp was 160 and it started. I did not notice the temp when it died while running. That's my next
mission.

[jrdowd]

JD thank you. One full bottle of HERT in a 1/2 tank cured my problem. It hasn’t happened the last 3 times out.


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[bigmyk2k]

...It could be an electrical issue but some of your description describes one of two issues, no fuel or no spark. So, get a fuel water separator additive (HEET) is the brand I get locally and it is cheap. Put in twice as much as directed. Run the boat and see if this helps. If this helps you may not be maintaining your fuel tank as needed and repeat the procedure...

Whoa, I'm definitely one of the ones that didn't know you had to do specific maintenance for your fuel tank. I'm a new and first-time owner. Bought my '96 Sport Nautique knowing it had some issues, but it did run. Actually had it out for a few hours a couple of weeks after buying it (would have been sooner, but I hit two deer at the same time driving it home from buying it and totalled my tow vehicle, still trying to find a replacement 6 weeks later, but that's another story).

I've changed the oil and impeller, and fullly filled up after that time with Ethanol Free gas (think it was a Top Tier brand, but not 100% positive). It had an idle surge, but not really concerned about it stalling. I also ran it briefly on a hose a few times while trouble shooting some other things, and again just before taking it out again (about 2 hours before we hit the water).

The next time I took it out was this past weekend, and the first time we took people with us. It started fine at launch and idled around in the no wake for a couple of minutes (again with the surging), but then died. It started back up and idled for another 30 seconds or so before dying again. Then started again and ran for about 5 seconds, then dead. After that, it would turn over and sound like it was going to catch, but never did. Had to paddle back to the launch ramp, which fortunately wasn't very far.

I was thinking it was the fuel pump or filter, but now I have something else to worry about. The previous owner winterized, but stored it covered outside. He had put some gas in it before we bought it, but I had to put in 18 gallons after the one time we used it (and it has a 24 gal tank), so it was definitely stored mostly empty. Trying to figure out all the things I need to troubleshoot before I can trust it again. This just added something else to the list.

[SilentSeven]

Boat's new to you?

I'd be deliberate and give it a full tune up first. New plugs, ignition wires, distributor cap and fuel filter. Check the engine timing and adjust if required. Carefully inspect engine and make sure all the sensors are plugged in and the connections are free of corrosion. Then do a test run to see what you have. If you still have issues, check the engine fuel pressure at the rail.

Good luck.