1994 Sea Doo GTX blows 5 amp fuse

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Rivergator

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By reading related posts regarding the subject of blowing fuses I have answered many of my questions already. I am pretty sure that I fried my MPEM. Before I go out and spend the money on a replacement MPEM I want to be absolutely sure that the MPEM is the problem and not something else. I read a lot of mentionings of the stator. Does that stator part apply to my 1994 GTX? What is the stator anyway? Is there a sure fire method of testing my MPEM to make sure it is the culprit. I have seen the list of ohm values for all the 8 wires of the MPEM and done the test. Btw my MPEM is 278000413. They are pretty much in line with what the list says. With everything disconnected and the MPEM removed from the box, can I apply power (-) to the black ground wire and (+) to the red wire (the one that was connected to the solenoid) and see if the fuse blows. And if it does I would think that the fault has been clearly estabished, or am I overlooking something and this test is misleading.
 

rvaughn704

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The only sure fire way to know is to out in another MPEM from another ski and see what happens.
 

Rivergator

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Yeah and what if the problem is somewhere else and I blow that one too. I am sure there must be some sea doo techies out there who know how to test these modules or at least have some idea how to isolate the problem.
 

SpitAndDirt

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........ What is the stator anyway? Is there a sure fire method of testing my MPEM to make sure it is the culprit. I have seen the list of ohm values for all the 8 wires of the MPEM and done the test. Btw my MPEM is 278000413. They are pretty much in line with what the list says. With everything disconnected and the MPEM removed from the box, can I apply power (-) to the black ground wire and (+) to the red wire (the one that was connected to the solenoid) and see if the fuse blows. And if it does I would think that the fault has been clearly estabished, or am I overlooking something and this test is misleading.

If you can perform this test with the MPEM removed from the ski and the fuse DOES blow, then you can pretty much assume the MPEM is toast. Now, if you are a betting man, you could try to see if you can remove the potting compound and search for a blown diode. Over on PWCtoday.com, there have been a few threads about people fixing their dead MPEMs because a $4 diode shorted out.

To answer your question about the stator: It is the component that sits underneath the rotating flywheel in the front of the motor. There is only a static resistance test for the stator to see if it has shorted internally. As the magnets embedded in the flywheel rotate around the stator when the engine is running, Alternating Current is induced into the stator coil (a stator is just a coil of wires around a iron core). Since the battery is charged by Direct Current, the A.C current from the stator must be rectified and regulated into about 13.5 volts DC for use by the MPEM and for battery charging. Your car operates the same way, only the Stator and Voltage regulator (along with a Rotor) are all self contained inside your car's Alternator.

Just FYI, for your year ski, there is a second coil that looks like a stator, but is actually the charging coil for the Capacitive Discharge Ignition (CDI) system. The manual will illustrate it better than I can describe.

Normally, if the motor is still in good physical condition, the three most common issues that plague most all pre-2000 Sea-Doo's are: 1) Fuel system issues caused by Tempo fuel lines falling apart internally and clogging the INTERNAL carburetor micro filters. 2) Original OEM voltage regulators going bad for various reasons. 3) Engine Starting and Charging issues caused by corroded or loose grounding points, cheap aftermarket Chinese starters, and failed starter solenoids.\

The key to this issue is to see if you can run the ski for about 5-10 minutes without having the voltage regulator hooked up. This means unplugging the Red wire coming out of it from inside the electrical box. This way, you are running straight off the battery without the possibility of any stray AC current "leaking" through a failed charging system. If the ski runs fine, and you don't blow a fuse, then you can troubleshoot further into a bad stator or voltage regulator or both.

Download a FREE service manual for your ski from www.seadoomanuals.net
 

Rivergator

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Thanks SpitandDirt, that was a lot of good helpful information. I will take the MPEM module out of the e box next week and do my test. If the fuse blows I know the thing is toast. I saw some of the postings about repairing the module and yes I will try to do it. Nothing to loose, it's fried already. I just have to find that diode. Its a Motorola MR2535 if I am not mistaken.
 

sixfigures

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The stator has 3 fields of 2 amps each, those are the 3 yellow wires at the rectifier, if you leave the red wire connected and un plug the 3 yellow wires, with the engine running carefully plug in one yellow field wire at a time, when you plug in a bad field it will blow the fuse, you can actually leave that field unplugged and run on the other 2 fields this will reduce the charging to 4 amps rather than 6 but usually that is all you need.
 

Rivergator

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Ok. I removed the MPEM from the e-box and tested it all by itself with nothing plugged in to it, except ground to nymber 7 black wire and 12 V to the red number 2 wire on the MPEM and the 5 amp fuse blew immediately. Now I know that this module is bad and I am going to see if I can fix this puppy myself. Correct, a number of posts have been made covering this repair and there was always talk that the diode is a MR2535. Well, I removed the potting compound and got to a big diode right next to the 5 amp fuse holder. I am pretty sure that is the culprit, but it is a T6A40L. Is this the right diode or am I barking up the wrong tree here.
 

Rivergator

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In the meantime I was informed that these 2 diodes are not related. I was on the wrong track. I would love to hear from someone who has done a similar repair on a 278000413 MPEM. In particluar where this MR2535 is located. It will save me the trouble of removing a lot of unnecessary potting compound trying to find it. Any help is appreciated, thanks!
 

Rivergator

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Does anybody have a picture of the circuit board of the MPEM 278000413 with the potting compound removed or have any knowledge where the diode MR2535 is located on the board? Any help is appreciated, thanks!
 

Rivergator

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Problem solved. I found the diode MR2535L and it was bad. Now I need to get a couple of these diodes (I always like to have a spare) and I am on my way. Thanks everybody for your help.
 

GA_Boater

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Could you possibly share the location of the diode mr25357

Rivergator has not been in the forum for almost 3 years and this thread has been dormant since 9/14. Please start a thread of your own for answers.

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