How do I test my magneto (stator)?

[dperkinstx]

20A Wow, what does the manual say ? I'm guessing thats wayyy to much.

From my Sea Doo manual, page 08-03-01:

The charging system is protected by 2 fuses. A 15 A fuse is mounted on the MPEM and a 20 A fuse is located in the rear electrical box.

I don't know what the other 20A fuse in the rear box is for, but I'm confident the 20A I replaced was supposed to be a 20A.

I took a trip to Virginia at the end of July. I pulled my three Doos up there with us. Just before leaving, I got "12 V Low" errors on both of my GTX RFIs. I wanted to take them with us so I brought two trickle chargers with me. I posted my issues to this site and most people responded that it's most likely my rectifier/regulator. Comments were made to the effect that these regulators fail on a regular basis. One person said his parts guy even knows the part number by heart because he orders them so often.

Since I was there for a week and wanted to use my Doos, I took the two Doos to a place called "Boat Doctor". He charged me $120 to tell me my '98 had a low battery and my '99 had a bad regulator. Because of what people on the forum told me, I was expecting the bad regulator diagnosis, but bad battery? I had just charged it overnight before taking it to him.

Charging the batteries overnight got me through the week. Charging the battery on the '98 did indeed make it's "12V Low" warning to go away.

I found a good price on regulators on ebay while on vacation and bought two. When I got home from vacation I assumed the regulator was bad (the mechanic said it was). I replaced the regulator, hooked up the flush hose, then ran the Doo for 5-10 minutes in the driveway. The warning never came on. The Doo sat in my driveway for probably a week before going for a ride. The battery wasn't charged since I got home. When I put the Doo on the water, it took probably 3 minutes before the "12V Low came on". I got back to the boat ramp and killed the machine. When I tried to restart it, there wasn't enough juice in the battery for it to crank (this was not the battery the mechanic said was low). So I assumed the battery must have a dead cell - I replaced the battery. Next time on the water it took probably 5 minutes before getting the "12V Low" warning. I killed the engine, then restarted it. The warning would go away for a minute or two when I did that, but it always came back. According to others on this site, the next logical progression is the stator. So here I am asking for help on testing the stator before getting onto ebay and buying one. Fingers crossed it was just the fuse.

 

[dperkinstx]

put a voltmeter on the battery, start engine and rev to about 3000 rpms, for a short time and tell us what it reads , if it reads above 13.0 - to around 13.5 , its good to go

I ran this test and got 12.9. That's a lot better than the 12.2 I got earlier today, but not where you said it should be. My '98 got a 12.8 when I tested it this morning. Does that mean both skis have more troubles ahead?

 

[richardpr]

i got a stator for cheap if you need one

 

[Dennis]

OK, I'm not trying to be a a**hole but what this thread does NOT need is more people jumping in and confusing the issue.

dperkinstx,
1. The correct size fuse is 20 amp.
2. The other 20 amp fuse is the main power supply for the MPEM.
3. The 20 amp fuse probably blew because of the faulty regulator.
4. The 20 amp fuse probably did NOT blow because of a faulty stator. The test you did show it to be good.
5. The 12.8 and 12.9 readings you got are probably a bit low probably because of the short time you ran the skis' and the batteries are fully charged.
6. If you bought cheap aftermarket regulators off ebay you will regret it. You will experience nothing but heartache and probably faulty stators in the future.

 

[dperkinstx]

Dennis, you've been a great help. Below is the rectifier I bought on ebay. Am I going to regret having it? I've also had someone tell me a bad rectifier will have a bump on the bottom of it. Mine doesn't. Perhaps my original rectifier is still good and was misdiagnosed because of the fuse.

http://www.ebay.com/itm/271025441537?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

 

[Dennis]

Thanks.
I've seen alot of regulators go bad causing the fuse to blow. That's why the fuse is there.
I'm not sure if that is one of the ebay regulators that cause issues or not. Price seems too cheap. Private message Griz400 and ask him. he would know. He's the RFI expert. :cheers:

 

[slank]

Thanks for all of the good information here guys. I have some troubleshooting to do on my one of my 99 speedster motors that doesn't seem to be charging the battery. Going to start at the easy (fuse replacement) and move on from there. Luckily my other motor is charging or I would have noticed the problem a lot sooner via a dead battery! I have a voltage meter (cheap Wal-Mart meter) installed in my 12v socket for quick reference and had I not sucked a tube rope into the good charging motor I never would have noticed the issue. I'm hoping for a bad fuse, but since i bought the boat this season from someone who had it sitting for a few years there is no telling.

 

[Sportster-2001-951C-Stock]

The first thing that I would do when troubleshooting a stator type charging system, is to check for battery voltage at the red wire output of the rectifier/regulator while the engine is not running. You should measure at least 12.5 volts there, this is your battery voltage.

Assuming your battery is properly charged, it should measure at least 12.5 volts, if after setting static for 24 hours, it should measure this voltage.

So, assuming there is no battery voltage at the red output wire of the rectifier/regulator, then there is an open circuit between this location and the positive terminal of the battery, or your negative battery cable is corroded. Most often, there is a blown fuse, other times a loose or corroded connection in one of the connectors.

Once battery voltage is confirmed at the red output terminal of the rectifier/regulator or a fuse is found blown, it's time to test your stator. The stator will have either two or three yellow wires running from it to the rectifier/regulator, these wires carry AC current from the stator to the rectifier/regulator. To test the stator, measure resistance between the yellow wires, these should all be more than 0.1 and usually near 1 Ohms. If all looks good, then also check from the yellow wire to ground, this should be an open circuit, with no continuity.

The next step to troubleshooting your charging system is to confirm if it is actually working. To do this, I prefer to take my boat with a properly charged known good starting battery to the water and run it for at least several minutes. The battery should measure at least 12.5volts before starting the engine.

Next, start the engine and allow it to warm up for several minutes before measuring the battery voltage again. At this time, the battery voltage should have increased to somewhere between 13.8 volts to 14.4 volts. Any higher or lower than this range indicates your rectifier/regulator is malfunctioning for whatever reason, or if too low there is a heavy electrical load on your electrical system such as a large stereo system or a dead/low battery, for example. Also, confirm the metal case of your R/R has a good ground, otherwise it cannot regulate properly. If this test fails to the high or low side of this range, the R/R itself is bad or poorly designed. There are decent aftermarket regulators out there on ebay, and there are ones that should be tossed in the garbage. I've bought both, so I know they're out there.

 

[griz400]

here is the one i put on my ski now, has lasted a couple yrs, and still working http://www.newjetskiparts.com/product_info.php?cPath=524_531_749&products_id=70969