Troubleshooting engine shutdown issues

[Clovertucky]

I own a 1994 Ski Nautique and it’s been a bulletproof tournament boat until our last trip to Lake Sonoma. At the end of the day going across the rough open part of the lake a large roller was headed our way and I backed off on the throttle and the engine shut down. It would fire but only for a second and then immediately quit running. After checking the carburetor it was determined the engine was getting fuel. Talking to a retired auto mechanic he said it sounded like a exhaust blockage, the GT40 engine has a carburetor and the Invertaflow two into one muffler. Getting the muffler out today and checking it out. Any help would be appreciated!

Phillippe

[wtrskrs]

When you say it ran a second, did it run for a second or two after you released the key from the start position? Or when you released the key after it started it then died? If it is the latter, you could have a bad ignition switch so the coil isn't getting power when in the ignition position (but gets it in the start position). I was going to mention looking at the fuel pump, but that doesn't see to be the issue. How was it determined there is fuel?

One other thing to try is to disconnect one plug cable and set it up such that the spark will jump to ground. When it cuts out, if there is no spark while it is spinning down, that is confirmation of an ignition problem (although you might have to give it some throttle when you start it so it spins up to higher RPM so you have more time to see if it still sparks while spinning down.

Also, I don't know about older ones, but of course check your safety lanard switch. If it is not seated correctly or has come off, there's a possiblity that the engine could spark while starting but when the key is released, it stops. On my MPI GT40, it won't spark if the lanyard is off or the switch is broken. But it may be different with an older engine.

I don't know enough about blockage to speculate about exhaust blockage. But I would think that you would have noticed something if a piece of muffler fiberglass broke off and started blocking the exhaust. I wouldn't expect it to be sudden.

Did the big wave have anything to do with it (water over the bow, etc.), or was that just why you slowed down and the engine stopped?

[NautiqueJeff]

Yep, sounds exactly like what a disconnected or failed safety lanyard switch will do.

[Clovertucky]

Thank you so much for your help! I feel like such an idiot it was the safety lanyard I just went out and checked it. Sure enough the lanyard was laying on the floor of the boat. I must have knocked it off in the rough water. My old Mastercraft had one on the dash which was a better location and a lot harder to dislodge , at 65 my brain and eye site is going away.

Philippe
Stuck in Lake Sonoma without a salmon course☹️ Sure miss Santa Clara County Waterski Club’s pond!

[NautiqueJeff]

Glad that's all it was. That's an easy fix!

[DealsGapCobra]

I love a simple repair!


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