787 Magneto Voltage Test

[etemplet]

I have a 1996 GSX 787 and I want to verify if the mag is bad but I'm not sure how to measure the voltage on the yellow wires inside the gray box. I pulled the connectors back so I could clamp the multi-meter leads to the yellow wires. Where do I connect the leads for the test? Here is what I did.

I placed the leads on the (3) yellow wires, alternating between the wires while revving the engine. I got about 7 volts reading on the meter no matter which wires I swapped to.
Next I placed the negative on the ground in the gray electrical box and and placed the other lead on each of the three yellow wires. Basically the same 7 volts.

I tested the red wire and grounded the black lead and the meter read 13.2 volts when I revved the engine. Kinda of confusing to me. I was expecting battery voltage on the red and black wires if the mag wasn't putting out. Help is appreciated.

 

[etemplet]

LOL, I guess I'm just to fast. to wait for responses. LOL I did more tests on the ski electrical system. I unplugged all 3 yellow wires from the rectifier and got AC readings of 40+ volts so I replaced the rectifier. I tested the voltage on the wires with the new rectifier connected and I was reading 40 volts on the yellow wires. Voltage to the red wire was in the 13 volt range. Looks like that was the problem but knowing how to check these things is important, replacing parts doesn't reveal as much.

 

[etemplet]

Testing the electrical system in the jet skis has always been a challenge for me. I always worried that I might screw something up as we all know how delicate these systems are to voltage spikes and reverse connections. MPEMs ain't cheap or available. LOL The manual generally suggests using special Seadoo connectors and diagnostic hardware which I surely do not have so we have to find other ways to accomplish accurate tests. I guess that is what makes working on these such an interesting adventure. It's always something and the deeper we go the more we learn. Almost to the point, "Whatever don't kill you makes you stronger."

 

[burtshaver2021]

I would definitely help if I could but electrical is a very weak spot for me, not that I have any incredibly strong shits when it comes to repairing these seadoo’s which is why when purchasing them I always lean towards ones that turn over and have spark. I’m looking forward to digging into a little electrical diagnostics sometime in the future, glad you figured it out

 

[artr]

Good practical active test for the stator. If you look in the shop manual the active test is with a proprietary test box.

 

[etemplet]

I would definitely help if I could but electrical is a very weak spot for me, not that I have any incredibly strong shits when it comes to repairing these seadoo’s which is why when purchasing them I always lean towards ones that turn over and have spark. I’m looking forward to digging into a little electrical diagnostics sometime in the future, glad you figured it out

This GSX I'm working on for a local guy, helping him out but I had spare 787 engine so I can get rid of that too. This ski has everything wrong with it but it is definitely making me "next level" testing these components. I think 3 jack leg clowns in a row must have owned this poor ski. It would have never run again.

 

[POPPS]

Just make sure you are on at least 50 v AC not DC,,,rev’r up with each pair of yellow wires,,, and you will be fine I think

 

[etemplet]

Just make sure you are on at least 50 v AC not DC,,,rev’r up with each pair of yellow wires,,, and you will be fine I think

Thankfully my multi-meter is smarter than me but I did set it to read AC.... LOL Good to hear from you. Check my post on the Carbs. I need some input.