Need Help Testing Rectifier Please

Chadwick82

Recruit
Joined
Aug 6, 2023
Messages
4
583076 is the one I have, want to make sure I test it correctly. Watched a ton of videos but they all looked different. I have a fluke multimeter. The rectifier has a thick red wire that goes over to the positive terminal, then it has 4 wires that go to a terminal strip. Yellow, Yellow Gray Stripe, Gray, Purple. Thank you!
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,087
That looks to be a voltage regulator. They are not as easy to test as a rectifier. Actually the test may be to measure the voltage at the battery under different RPMs.
 

Chadwick82

Recruit
Joined
Aug 6, 2023
Messages
4
That looks to be a voltage regulator. They are not as easy to test as a rectifier. Actually the test may be to measure the voltage at the battery under different RPMs.
My manual says 9 amp stators will not have a regulator and mine 9 amp. How can I tell the difference? Maybe it's the wrong part on the motor?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,087
A full wave rectifier is composed of 4 diodes wired in a bridge. The internet will give you a diagram. There are two connections to the stator wires and a connection to -12VDC and another connection to +12VDC. Mercury uses rectifiers that have the case ground connected to the -12VDC.

Diodes only allow voltage to pass in one direction, so the test is to check each diode and then switch the ohmmeter leads and check it again. Analog ohmmeters work just fine. Digital ohmmeters usually have a setting to check diodes.

You should have zero resistance on one test and infinite resistance on the next test. So 8 tests to determine if the rectifier is good.
 
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