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12 Volt Low

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Yes, the Carbed skis I think have the built in, the DI's and RFI's have the external units.
 
The carbed 951 has an MPEM internal rectifier and those are pretty reliable, more than the external ones seems like. The DI injected ski uses an external regulator that's heavy duty and you can swap to that one if you want by doing a little rewiring. But if yours is carbed then make sure to check the 15A fuse on the MPEM to be sure it's not blown.

And I would ohm out the stator as well, just to be sure. Should have around 1 Ohm or slightly less of continuity between each of the yellow wires and no continuity to ground from any of the three. If stator is open for whatever reason, the rectifier will have no output and battery will discharge while running.
 
Thank you for the information. Id like to test the stator as well. Is there an article that shows me how to properly test it? Im not too familiar as to the exact location. Its the 15amp fuse located in the front MPEM? I checked those fuses last week to see if it was causing an error with my fuel guage. Im wondering if maybe that fuse isnt completely seated seeing that before I did that the ski was running great with no "12volt low" issue. Thanks for helping me out. I really appreciate it
 
Here's the electrical schematic of a 951 carbed ski, most are very close aside from minor differences such as optional gauges. You can see the three-phase winding of the stator (A Permanent magnet 3-phase AC generator) is connected to the MPEM connector #2, pins 24,25,26 using these three yellow wires to conduct the AC from the winding in the magneto housing to the internal rectifiers built into the MPEM.

Pull this connector #2 off the MPEM and use an ohmmeter set on lowest scale of resistance to measure between any two of the three yellow wires, measure all three. (FWIW. You can even use a power source and a test light to check each of the three conducts to the other two as a rough test but this doesn't tell you exactly the resistance.)

Also measure any of the three or all three if you like, to ground, there should be infinite resistance.

The service manual has a complete troubleshooting section for all three models produced tduring the year, follow the section for the 951, the 787 carbed motor uses the same stator I believe, and you can use the regulator from that ski also if you like. The DI ski and the 4-tec ski have a heavier duty regulator for the additional current and power of the fuel injection so that one can handle anything you throw at it.

There are a few fuses on the MPEM, and a spare or two. 5A is for the MPEM logic controller itself and feeds gauges & ignition, the BATT 15A is the regulator output fuse that goes through the harness to over through the e-box where the ignition coils are and then through another 15A fuse in the ebox (everything is dead if the 15A e-box fuse is blown) on the way to the battery to keep it charged.

So if there's a problem, either the magneto stator is damaged, the 15A BATT fuse on the MPEM is blown, or the regulator quit regulating.

So measure the 3-phase magneto stator windings and see what you get, should be ~ 1 Ohm from any single yellow to it's sister and it's brother yellow wire. There should be complete open to ground for all three (isolated from ground). If magneto stator is shorted to ground, this will blow the MPEM 15A fuse, but if the magneto windings are open there will be no AC power to rectify.

Let's focus on a resistance/conductance measurement on that magneto stator winding and confirm it's good, then go from there.
 

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Sorry been a long day so just pull the 2 plug and touch one probe to one yellow wire and the other probe to one of the other yellow wires and then the third and get the reading?? Just want to make sure i do this right
 
Here are the pictures of my tests. We are pretty sure the stator is fried is that what this means??

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It looks like one phase of stator is open. Also measure from the good ones to engine block ground should normally read OL (open circuit), probably you read "OL" I think.

Some meters would display an open circuit differently, mine displays "1" in left-most digit for open circuit and 1.1 in right-digits to represent 1.1 Ohms. "OL" on your display indicates no path for current, ie: open circuit.

It seems the wire winding of stator is "open", probably where the wires were twisted together it's not making connection.

More clearly, it appears the stator is defective or perhaps the wiring to the stator is broken. I bet the stator itself, is the culprit.
 
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Well I pulled the pipe and am currently puttling the face off the motor to pull the stator. Based on what i have heard and what type of readings we have gotten i am about 95% sure at this point its the stator. 2 of the 3 wires were good whenever we tried the other wire to anything we got nothing

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beachybeach24 said:
Well I pulled the pipe and am currently puttling the face off the motor to pull the stator. Based on what i have heard and what type of readings we have gotten i am about 95% sure at this point its the stator. 2 of the 3 wires were good whenever we tried the other wire to anything we got nothing

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Click to expand...

Agreed, it appears your stator (or the wiring to the stator) is on the fritz (broken).
 
Im hoping at this point its the actual stator seeing that seadoo doesnt exactly make it easy to get to and had to pull the pipe to get to it. Im this far the stator is being replaced. Is there another test i can run at the plug?

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Well...... thought everything was going smoothly. Now i have 1 bolt left holding on the cover somewhere near my motor mount. Im about to take a sledgehammer to this damn thing

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Just as hard to get at in the boat, looks to me like motor has to come out.

The test at the magneto connector is the same, just different location and would eliminate the possibility of a broken wire in the harness or burned connector pin. I'd say a low probability the harness actually failed.

Use locktight on the stator winding screws b/c if they come lose the parts get slung around by the flywheel and beware stuff getting stuck to magnet, no lose or stray parts allowed.

Have a look at starter bendix gear assembly, kiss it for luck or if rough in some way good time to do something?
 

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There are 11 bolts that hold that cover on. I have 10 of them off the last one is on the bottom right in front of the hull. I can lift the front of the motor just cant lift and loosen the bolt myself. My new stator came in today so tomorrow my new exhaust gasket is coming in. I have a buddy thats gonna give me a hand. Noticed my oil tank leaking at the seem as well. So im replacing that also. Im hoping to have it back together within the next few days.

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