I should have a thread on here about this stuff. Basically if you have continuity between the black and Red ring terminal you're shorted and the MPEM is bad. I had this problem on my first ski but it was the rectifier that caused the problem You have to eliminate the problem. I have 2 MPEMs I repaired and are set up for testing. I soldered wires to the diode terminals and now I can change the diode easily.
I have some MPEMS for the old skis. Hit me up I'll make you a good deal. I can also lend you the test MPEM so you don't blow up the replacement.

That was my concern when I did mine. I was really knew to Jet Skis... it was my first one.
I've done all those tests on 3 skis and spent a lot of time troubleshooting. Even if the readings are in tolerance that doesn't mean the MPEM is
good.
.
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