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RXDi limp mode

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Thats a really good question.

I don't believe it went into full limp mode as I could still rev it up with no issues, or change in RPM. But, this is a test on the trailer only. I didn't try to rev it over 4K though. I never gave limp mode much of a thought as I was only researching the maintenance warning side of it.
was Qcustoms ski was going into limp mode since he found his temp sensor disconnected? Sounded like it was just an idle issue.

Not 100% sure.

Yeah, I think it's safe to assume it would go into limp mode if voltage drops under 12.5v or so, b/c the fuel mapping probably can't compensate thus the air/fuel ratio would be incorrect so the MPEM should go into LIMP. It should recover from limp and go back to normal if the voltage came back into operating range, as if the battery had been discharged from cranking and it took some time to bring the system voltage back up.
 
And there are two different LIMP modes, one will allow 4000RPM operation and the other will only allow idle. So my GUESS is if the temp sensor is disconnected it will only idle and if the system voltage is out of range it can only rev to 4000RPM

The service manual explains the types of faults that can trigger a 4000RPM limit and differentiates them from a fault that limits RPM to idle speed. Some sensor problems trigger faults that limit RPM to idle speed.
 
Doesn't charge? What voltage's did you find? Doesn't sound like a stator problem seeing you recently had 16v with the old R/R

What brand did you purchase & install? New?
 
I know I mentioned this earlier, but if you have a hard time finding one in your area, I would consider trying one from a street bike before buying a cheapo repop. This is all at your own risk of course as you have to figure out the wiring & splice the oem connectors, However, my theory is the street bikes run a fuel pump, 4 fuel injectors, twin bulb headlights, tail light, blinkers, etc. Ironically the one I installed bolted right in, I just had to enlarge the mounting holes one size. They have a much larger heat sync area too.

I have not proven the longevity of them, or even the safety of using one, but on paper it makes sense.
The street bike mine came from, has an electrical system rated at 13.5-14.5 @ 25-26 amps at( 378 watts. )

Someone could confirm this, but I think the seadoo's are around the same specs?

Might be safer for me to be the guinea pig on this one too. But voltages are perfect on the trailer. ;)
 

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Ok so on key off we have 12.82. Key on we have 12.7
Idle we have12.54. At 4k rev we have 13.


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Hhhmmmm, your idle voltage is still too low & so is rev'd

to check the stator, you need to measure the resistance of each of the three windings. resistance of each one should be between .1 & 1.0 ohms. looking at the picture below, you can see how you need to connect to the three wires to measure each winding. think of the three wires as points of a triangle & you need to measure the sides between them. easiest way is to hook the black & red of your meter to any of the two yellow wires. then move the red probe to the remaining yellow wire, after that. move the black to the wire the red was on in the first measurement. That will give you three measurements, one of each winding. Then check each yellow wire to engine ground. There should be no measurement at all between engine ground and the stator wires.

Lastly, flip your meter to A/C, start the ski & measure the voltages at idle between all three wires in the same way you tested resistance. Be carful not to let the wires touch anything! also test them at 3500ish RPMs. should be between 35-70VAC

With all this said, it seems odd that the stator would be bad seeing you had over 16VDC in the beginning of this problem.

If it helps, I can test my DI & give you the results for comparison.




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Agree on the need for testing the stator, and EXPECT you will measure closer to 1 Ohm than 0.1 Ohm between any two of the three, also totally open to ground on all three is necessary, of course.

RR output voltage should be ~13.8vDC.
 
Ha, that's a great question but I don't know in the case of the Rotax 951-DI !

I can tell you this has been rather common on some other motors though, where the bonded strip magnet adhesive fails and the magnet comes lose from inside the flywheel and sticks itself to the stator. Common issue for some outboard motors, haven't heard this about any Rotax motor yet.

Honest answer is, I don't know if the 951 DI has this type of a bonded strip magnet like many outboard motors or if the magnets are cast into the flywheel, but if the DI uses a one-piece bonded magnet it's entirely possible for the adhesive to fail, I've seen this before many times.

Sorry I don't have more detail concerning the DI specifically, you need advice from someone who has actually seen the inside of the DI flywheel (not me).
 
Had one in my hands about a month ago, but I never paid attention.

However, if thats a magnetic mess, I would expect the voltage tests would fail as well.

Seeing these things so accurately idle at 1450RPM's why don't you do a voltage test on the three stator windings at idle & post your findings. I am willing to test mine as well so we can see if your stator is providing enough idle voltage.
 
Ok so I had enough. I pulled it out. All seems ok on stator tho.
But sparkie going to double check.

Further more I noticed a few issue with this ski wich I'm not happy about.

When I removed the motor I noticed pipe work un connected underneath.

And I saw this cover only screwed down with 3 bolts and bulging open and corrosion for Africa along with a broken plate and glued together.
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Noticed all this oil everywhere
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So it feels like 1 problem leads to next wich I'm upset about. The glue is new and obviously Murray must have known bout these issues. Should I approach him or leave it?

I just want it fixed.


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Top end has for sure been apart looking at the head bolts. Are the larger red o-rings missing below the air injectors? (not the small black ones on the injector itself) I'm not sure why else you would have so much oil leaking from there, unless it just looks like its coming from the injectors.....

The cooling fins look like salt water exposure. I'm guessing the ones on the bottom of the block look the same way. Are these the lines that have been disconnected??

Looks like your missing one of the two exhaust mounting bolts too. Or did you remove it?

was there a stud in the bottom hole of the manifold?
 
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To make matters worse I found this lying in the intake shute
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So NOW I'm really worried.


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I'm only guessing but I would think that a broken reed would cause the engine to run crappy triggering the knock sensor...or something.
 
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