Need some ideas on a problem with ski shutting off

[Baja 252]

So, naturally I'm not at the lake and my son calls with a ski problem. It's an 08 Superjet with stock ignition with newer MSD plug wires and MSD enhancer. Ski runs fantastic the past 3 months, but last weekend it died all of the sudden while he was just cruising around. Strange, but it fired right back up and ran great the rest of the day. Next day it does it twice, fired back up instantly and runs great. He describes it like you hit the stop button when it dies. He checked out the fuel system and all seems good. Sounds more like an electrical issue to me with start/stop button.

This morning he says it's dying every 5 or 10 minutes of riding, but fires up instantly and runs perfect for another 5-10 minutes or so. By the afternoon it only runs for a minute or so before it dies. I had him lower the idle speed so it would die if he fell off and unplug the white plug of the start/stop switch harness (black and white wires) to eliminate the stop button switch from the circuit, but it does the same thing with it unplugged. To me this means it's something else.

Obviously when I get down to the lake I need to look at the wiring and in the ebox for something loose and grounding out, but if that's it, it seems strange to me that it always fires right back up.
Does this problem sound familiar to anyone or have any other ideas of things to look at? Could a stator or CDI do this?

 

[DylanS]

MSD enhancers do all sorts of silly stuff when they go out, I’d swap for a known working one and give it a shot first.

 

[Harbor]

Might try completely venting the fuel tank to rule out vapor lock

 

[OtherDonnieGuy]

First place I would look would be the Stop start harness in the ebox, could be grounding out inside.

 

[WFO Speedracer]

You sure the engine isn't seizing up, the more and more frequent intervals are sounding like it may be engine seizures

 

[Baja 252]

Thanks for the ideas everyone.

It's not an engine, oil or fuel problem, when it fired right back up it ran perfect. It's electrical. Most likely is the start stop switch, I just can't figure out how it would do it with it unplugged.
If it's a loose wire it seems strange that it fired back up everytime, but possible I guess. Makes me think the CDI may have issues, but I don't have a spare so it's an expensive part to throw at the problem.

 

[badvinny]

A few times I have had the exact symptoms with the tether switch in the start/stop switch. Take it apart, clean any corrosion off the sliders and the contact points, grease it up fresh and put it back together.

 

[Baja 252]

A few times I have had the exact symptoms with the tether switch in the start/stop switch. Take it apart, clean any corrosion off the sliders and the contact points, grease it up fresh and put it back together.

I would agree, but the start/stop switch is unplugged and it still does it.

 

[badvinny]

I would agree, but the start/stop switch is unplugged and it still does it.

Was the tether connected?

 

[Pro-pulsion]

I've had the mini-seize incident before from bad crank bearings opening up an air gap in the crank seals at higher RPMs leaning out the suspended fuel charge in the cases. I've also seen a fuel tank try to implode because the one way valve muffed up and wouldn't allow air in. The engine would draw out as much as it could, the tank would suck in and with a lot of force, eventually when air would weep its way in the ski would start and run for 10 minutes or so until the tank imploded again and no more fuel could be drawn through the lines.

 

[Baja 252]

Was the tether connected?

Yes

 

[Baja 252]

Interesting idea, but in this case when the ski dies it instantly fires right back up and runs perfect.
I haven’t had time to get to the lake to even look at it.
I’ll post what I find out when I tear into it.

 

[badvinny]

Yes

That is how it works if the tether is connected and there is a fault in the switch. Takes little time to clean it, a drop of moisture inside will do it.

 

[badvinny]

It usually gets worse also.

 

[WFO Speedracer]

Is this in salt water or fresh water, the reason I ask as I had it happen on my 650SX in Orange Beach, turns out the rubber boot on my switch was worn out and let salt water in, I do agree though unplugging the switch eliminates that as the issue, my question is what does the inside of the electrical box look like , it it clean or is it half full of water

 

[Baja 252]

Fresh water ski, ebox usually looks like new, but something could have happened recently to let water in I suppose.
Been so busy won't make it to lake til the 4th.

 

[Baja 252]

Update: Finally got a chance to take the ebox out. Sure enough it had water in it, based on the water mark inside the box about a 1/4" in the bottom. The screws were tight, box isn't cracked, gasket looked good and rubber grommets are tight and feel good. I have no idea how the water got in, the ski hasn't been swamped or even had more than the usual small amount in the hull when you ride.
I dried it all out, cleaned all the connections and let it dry out overnight. Installed a new gasket, installed the box and the ski fired right up. I was looking for an excuse to upgrade to a Zeel, but the MSD enhanser worked great all weekend.

 

[WFO Speedracer]

Usually there is no rhyme or reason to it , I see it a lot on sitdowns most of which have the ebox mounted fairly high in the hull and you would think a sitdown would see a lot less water in that area, I just know what I know which ain't much.

 

[Baja 252]

Well I spoke too soon, 2 hrs of perfect running and we lost spark again.

Pulled the ebox and we have about a spoonful of water in the ebox and everything is damp. Just taking the lid off the ebox and blowing it out with air, the ski starts back up and runs fine. Obviously water is getting in somewhere.

No, the ski isn't ever swamped or even run with more than the usual 1/2" of water in the hull they all seem to have. This is not a old crusty ebox, it is very clean and never had any issues with water before.

I checked the ebox for cracks, checked the fuse cover gasket and all the grommets. The grommets all look great, rubber is nice and soft, wires passing thru them are tight where they go thru the grommet. I also used a syringe to dribble water on the outside of the grommets around the wires to see if any water came thru, but nothing did. The ebox gasket is a new Yamaha one, installed correctly and I even put new screws in the box.

I'm at a loss as where the water is getting in, anyone have any ideas. I really don't want to use any sealer on it, that"s not the right way to fix it.

 

[DylanS]

Well I spoke too soon, 2 hrs of perfect running and we lost spark again.

Pulled the ebox and we have about a spoonful of water in the ebox and everything is damp. Just taking the lid off the ebox and blowing it out with air, the ski starts back up and runs fine. Obviously water is getting in somewhere.

No, the ski isn't ever swamped or even run with more than the usual 1/2" of water in the hull they all seem to have. This is not a old crusty ebox, it is very clean and never had any issues with water before.

I checked the ebox for cracks, checked the fuse cover gasket and all the grommets. The grommets all look great, rubber is nice and soft, wires passing thru them are tight where they go thru the grommet. I also used a syringe to dribble water on the outside of the grommets around the wires to see if any water came thru, but nothing did. The ebox gasket is a new Yamaha one, installed correctly and I even put new screws in the box.

I'm at a loss as where the water is getting in, anyone have any ideas. I really don't want to use any sealer on it, that"s not the right way to fix it.

If there’s that much water in the box with that little water in the ski there must be a big leak somewhere.. pretty baffling if you’ve checked all seals and grommets.
Sounds crazy but maybe plug all the grommets and fill the empty box with water to check for leaks?