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Bench Testing 1985 Merciury 50hp-4cyl- Electric Start

S

Sea Nymp

New member
I have a question regarding the rectifier on a 1985 Mercury 50hp- 4cyl, electric start.
It appears that the stator is shot. I wanted to check the rectifier to make sure it was ok.
I did a bench test shown in my Mercury Outboard Shop Manual. Also found same test online


  1. Place/set your multimeter to the 1000 ohmmeter reading (RX1K, R X 1000, etc). See picture below.
  2. Place the RED lead to the ground (G) and place the BLACK lead to A and C alternating. You should show continuity.
  3. Place the BLACK lead to the ground (G) and place the RED lead to A and C alternating. You should NOT show continuity.
  4. Place the BLACK lead to the terminal (B)) and place the RED lead to A and C alternating. You should show continuity.
  5. Place the RED lead to the terminal (B)) and place the BLACK lead to A and C alternating. You should NOT show continuity.
  6. If your results differ, then the rectifier should be replaced.

After performing this test my rectifier failed all 4 test
I ordered two new ones, decided to test them before installing. Got the same readings as with my old one.
It appears the test is not accurate, or for a different rectifier. The book said that all Mercury square, black, 3 terminal rectifier were the same. It has two yellow wires coming from the stator, one red wire that goes to the battery.
1 is a Mercury OEm 62351A1- The two new ones are replacement numbers for this OEM

Can any explain why the readings are almost totally opposite from that the test says that they should be?
 
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