2000 Air Nautique left in rain and now won’t stay running

[Spessx]

Hi all

I have a 2000 Air Nautique with about 480 hours which runs (or ran) like a champ. Its got the GT40 PCM engime in it. We live in Texas and have had bad flooding this year. In an emergency my son and I had to scramble to pull it and the jetskis off of our dock before it ended up underwater. In our hurry to get things done, we put the cover on it and parked ot in the driveway. I didn’t think to pull out the plugs and the boat got water in it - not up to the carpet but definitely filled up the bilge area most of the way. It sat for days before I got back out and thought of looking at it.

I gave the boat a week to dry out and just tried starting it today. It will start but not run more than 30 seconds.

Any ideas where I should start to try and solve this? There doesn’t appear to be water in the oil. Maybe water in the gas?

[bturner]

My thoughts on where I would personally start on this......

If it was indeed running great before this, then we can pretty much assume the issue is moisture or the result of moisture related which on an older boat has plenty of places to infiltrate. To get an idea of where the boat sits mechanically/electrically my first questions and what I would be looking at if I were there assisting you would be.....

Fuel, Air and Spark
I'll take these out of order as I would lean towards electrical due to the soaking the boat took.

Electrical - This is where I would start. When boats are running, most people (including myself) will leave things alone and most times "if it's not broke, don't fix it" is good advise. However extended periods of that adage, while perfectly fine under normal operating conditions, can leave you exposed in less than ideal conditions, such as a good soaking. If you haven't done a cap/rotor in a long time or even if you have this would probably my first place to start. You don't mention how the boat was running for those 30 seconds but if it is barely running or is barely "catching" there's a good chance you're experiencing low spark or crossfire through the cap.

My first stop would be to pull the cap and see if there is any moisture or corrosion in the cap/rotor. WD40 is the miracle juice for moisture issue with electrical systems on cars/boats. Fun fact.... the WD stands for Water displacement. Pull the cap and take a look, if it's anything less than in great shape or you haven't done a tune up in years, replace it and the rotor. For the time being and troubleshooting, liberally spray out the cap with WD40, clean up the contacts and the rotor contact with some emery cloth then clen/dry it up. The idea here is to get it looking as close to new as possible. While you're doing this look to see if you can see any cracks or any other physical damage. Put it back together and try to start it again. If no joy or it's better but still not quite right you're going to have to do the same with every connector and electrical component.

I personally have not worked on a GT40 however I've seen plenty of posts on the relay people have had issues with that have caused issue with running. In this case I would be paying special attention there and any other electrical connections.

While on electrical connectors..... It doesn't take much to screw up electrical on a boat. since this is an older boat now would be a good time to also look at the primary engine wiring and grounding. I don't think this is the issue here but if you're marginal to start with poor electrical connections or failing wiring isn't going to help your situation. Time to nut and bolt your electrical if you haven't been keeping on top of it all along. Also, your primary ground is located on the engine block and on most boats sits pretty low. This would be something I would pay particular attention to.

Fuel - Unless you got a tank full of water out of this somehow, I just don't think this is going to be the issue. Rough running or missing issues, sure but won't run after a storm? I'm just not in this camp. That said if you're going to fire the parts cannon and you haven't done maintenance in this area in some time, this would be a great excuse to do so by replacing the water separator and filter and examine the contents of both during the process.

Air - Back to maintenance on this area. I've seen spark arrestors that hadn't been clean in years, or ever, where I wondered how any air was getting in the engine. Moisture is only going to make something like a dirty arrestor worse. This again would be a great time to clean the arrestor up. Very low odds of this having any effect here.

As you can see by where I spent my time here I'm all in on electrical and in this case the ignition system. If you haven't done so in years and you're ready to fire the part cannon, I would first try to get the boat running again so you don't end up making the problem worse or masking the problem with a massive parts drop. Once you have it running stable again you can start with the tune up.

[Spessx]

Thank you for the response and the ideas. The boat starts right up and runs but dies after less than 30 seconds. So, it is getting air, fuel and spark. I replaced the cap, rotor, plugs and cleaned the spark arrestor about a month ago.

Any ideas on what might cause it to stop running after only 30 seconds or so?

[bturner]

If we say that the electrical is good (which I'm not convinced it is), then the next step as outline above would be fuel. 30 seconds or so would be about the time it would take for the prime to run through the engine. If the engine runs well for that 30 seconds, (runs smooth without misfiring or bucking) then I would start looking at the fuel pump(s) (I believe you have a low and high pressure pump in this system) and the control circuit for the fuel system. These early PCM fuel injection systems were great when they were working and a bite when they're not. You have both an ECM and a relay that can be an issue with this system as well as the kill switch to throw into the mix to make an absolute mess of trouble shooting.

If I had to guess, you're getting the prime signal but not the signal to fire the pump to run the engine. There's a ton of posts on this on the internet. Sticking with keeping it simple and going after the low hanging fruit first, l would start with bypassing the kill switch. This is fairly easy to do by pulling the switch out and jumpering the connectors. Working my way down the least to most expensive culprits, I would next be looking really close at the relay and any connectors in line with it. I would pull each apart, clean everything up, spray it out with WD40 and try again. Relays are cheap, it it still doesn't work I'd replace the relay and try again. There's plenty of posts on these going bad or the connectors/wiring being corroded causing issues. The last item would be the ECM which I doubt is the issue but it's always a possibility.

Depending on your expertise and comfort level working with electrical, there is certainly enough information to start a logical diagnostic approach to troubleshooting this without firing the parts cannon. The left out in the rain for a soaking and leaving it wet still has me still in the electrical camp. The exact component is the part you can't diagnose from a thousand miles away.

Here's a couple threads on GT40 fuel issues to look at.....

https://www.correctcraftfan.com/foru...40-fuel-supply

https://www.planetnautique.com/vb5/f...ump-issue-help

[jpwhit]

I would suggest narrowing it down to the major system causing the problem. Fuel or Ignition.

Attach a fuel pressure gauge and see if the fuel pressure drops at the same time it cuts off. Also get a spark tester at an auto parts store or Amazon. The kind that you insert between the plug wire and the plug that lights up. See if you lose spark at the time that it cuts off. Now you'll know if you're chasing a fuel issue or a spark issue.

If neither of those, then I would check if the ECU is shutting down the fuel injectors. You can get a fuel injector Noid Light Kit at amazon. They flash as the injectors are pulsed. If they stop flashing when the engine shuts down, then the ECU is shutting down the injectors. That would likely be caused by a bad crank position sensor, cam position sensor, or bad ECU. Crank position sensor is low down on the engine and could easily have been submerged in water given the scenario you describe.