Seadoo challenger random stalling / intermittently cuts out

[Comeinhandy]

I thought I should share this in case it helps someone else. I had an intermittent stalling / engine cut out on my Seadoo challenger that took a year to diagnose and fix. Finally got there after going over lots of other stuff, but in the end it was a random disconnection glitch from the lanyard/DESS post/key that would reset the computer.
I only just got around to documenting the fix in a video, I remember reading of other people that had the same maddening issue, so hopefully the circuit in this video will help others fix it:

https://youtu.be/ZaQH3QUXGB0

 

[Dr Honda]

It's a common issue when they get old. You should have posted up here, and we would have helped you with it.

 

[Comeinhandy]

How did other people fix it? New DESS post and keys? Apart from the cost of that, I was slightly put off that route by posts I read where they changed all that and more and still had the problem. I work in electronics but never seen such a weird failure. The DESS post only ever glitches off and never disconnects for more than a fraction of a second. It doesn't make a lot of sense but even crazy thoughts like it was picking up random radiation discharges cross my mind! It behaved so random and glitchy and it couldn't be persuaded to fail by hitting it which would have worked had it been a corroded or loose connection. So weird!

 

[Dr Honda]

Don't need a new "Key". The lanyard code is held in the MPEM. Unless there is physical damage to the lanyard... all we recommend is to start with a cleaning. Make a paste out of water and baking soda, and polish the contacts. If that doesn't cure the issue... then just replace post.


Yes... you are right. A quick disconnect, or loss of communication to the lanyard with shut you down. BUT... it's not an issue, unless there is a problem. All my Seadoo's get bounced, and splashed, and don't have any issues with the system.

 

[Dr Honda]

One more thing...

If there is physical damage to the lanyard... then yes, you need to replace it. In that case... you have to get a dealer to program a new one for you. (or you need a Seadoo tool to do it yourself)

 

[Comeinhandy]

Thanks for your replies. One of the prior jobs was cleaning the lanyard key and post. In the video you can see they are both quite clean. Also tried the spare key, which was also cleaned. It made no difference. If they were rusty it would have been a problem but they weren't. The cut out was also not related to any movement of the boat, bangs or crashes and tapping the lanyard key/post didn't seem to make it fail either. It would just do it randomly, which is why it was so strange.
As the glitching is so strange I would be interested to know what is in the DESS post, has anyone taken these apart? Reed relay or hall sensor for magnetic sensing? Any electronics?

 

[Markhurst]

I believe I may have the same / similar issue. Was yours the single or twin engine model? I am in Hampshire, UK. Waterlooville to be specific and would love to chat if your local.

 

[Comeinhandy]

I believe I may have the same / similar issue. Was yours the single or twin engine model? I am in Hampshire, UK. Waterlooville to be specific and would love to chat if your local.

Mine is a single Rotax engine 110hp. The control system would be the same I guess.
I am in Ringwood, and am around for a chat.

 

[Markhurst]

OK, mine is the twin engine one, but odd that I am only getting issues with one. I'll pm you. Many thanks

 

[Fat Tony]

If you are having the same issue, its probably the same thing. I just replaced the DESS post on mine due to a similar issue. Weird thing about mine was that I used it last year and it had one glitch. Went to start it up this year to get it ready for the season and nothing... tried cleaning the contacts and everything. Ended up replacing it and the beeper. PS, it doesnt matter if its a single or twin engine boat, they all use the same style post, mine is a 97 speedster with twin 717's

 

[Markhurst]

If you are having the same issue, its probably the same thing. I just replaced the DESS post on mine due to a similar issue. Weird thing about mine was that I used it last year and it had one glitch. Went to start it up this year to get it ready for the season and nothing... tried cleaning the contacts and everything. Ended up replacing it and the beeper. PS, it doesnt matter if its a single or twin engine boat, they all use the same style post, mine is a 97 speedster with twin 717's

Thank you. I've tried the DESS post, but I don't think it can be that as the port side engine is absolutely fine. It only cuts out when I start the starboard engine.
I've ruled out fuel, oil, DESS, battery power etc. Must be electrical, but I'm stuck.

 

[Fat Tony]

So, will the starboard engine start and run by itself without the port engine running, or does it always cut out?

 

[Markhurst]

So my port engine, is absolutely fine. Will start, run and stay running no issues.
The starboard engine will cut out within 3-10 seconds everytime. If I run them at the same time, the starboard engine will take the port out with it.
I then have to go through the starting process again. Reset DESS etc.
Will restart no issue on the button when I've reset it.
It last marginally longer on the hose, if that makes any difference.

 

[Markhurst]

I've checked the oil pressure sensor and temp sensor, not those. Whatever is causing the issue, is cutting out both engines.

 

[Fat Tony]

Have you tested/replaced the voltage regulator?

 

[hotrodssnova]

Both engines share:
Fuel
Dess.

I would check / clean the dess. Then, filters on fuel system.

 

[Markhurst]

Know I've not checked the voltage regulator. Is there one for each engine?
I'd discounted the fuel and DESS as the port engine runs no problem and will run all day.
The only time I get an issue with the port engine, is when I try to run the starboard one and it will take both out.

 

[Fat Tony]

Yes, each engine has one, they are bolted to the stator cover on the mag end. I would disconnect the red wire on the starboard engine and see if you problem goes away.

 

[Magic Man]

Hello, did you ever get this fixed? Mine is doing the exact same thing..
I have rebuilt the carbs, checked all fuel lines, ran it on auxiliary tank, checked return line, checked all wire grounds etc.. Stumped. Any help or advice would be of many thanks..

 

[Magic Man]

Follow up> Nothing fixed the mid range intermittent slow die on random port and starboard except throttle past it aggressively and drop back to desired speed so long as not in rpm band of low to high speed jet transition. The boat runs very well otherwise.

 

[teamgreen737]

IF ANYONE IS EXPERIENCING BOTH MOTORS CUTTING OUT RANDOMLY (as if key is pulled) AND REPLACED KEY POST WITHOUT FIXING PROBLEM HERE WAS MY SOLUTION:


Your shifter has a sensor with two wires that let the motors and electronics know if its in D/N/R. I had removed my shifter/throttle assembly to fix a looser throttle lever and must have got this wire caught underneath it making it extremely tight and pulling connection. I fixed this connection and then cleaned and retightened my battery connections and problem went away.

 

[yacht1255]

Thank you very much