1987 Mercury Black Max 135 voltage regulator problem.

Rukus1

Cadet
Joined
Aug 26, 2018
Messages
11
Hi there,

I have a 135 Merc V6 that has been having charging issues. A few dead batteries this summer, a couple times having to pull it over with a rope.

Stator tested good.

New rectifier.

If I disconnect the voltage regulator I have up to 16 volts at the battery at high idle. However when I connect the voltage regulator the most I can get is 12.9V

I took another identical voltage regulator that works off a 150 Mariner of same generation, same problem.

Connections between regulator and rectifier are clean, wires are fine. Red wire to positive on rectifier and yellow to one of the yellow posts on rect.

Is there any way to test the voltage regulator? I have a hard time believing this one I just replaced is also no good. The issue is this regulator seems to be discontinued from Merc (88825A7) and aftermarket ones that claim to be replacements look entirely different.
 
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