93 mercury 150 efi charging system

[Deershooter]

I just bought this boat 2 months ago and found the batery going dead after several hours of use. I started to dig into it and found that the stator ohms out good. So I have narrowed it down to the voltage regulators. I just need to figure out which one it is or if it is both of them but I am not sure how to test them. Any help would be great.

[boatfixer]

Is the tach still working?

Remove the rectifier wires from the terminal block. Using a ohm meter, connect the black lead of the ohm meter to the rectifier base (ground), then one by one, connect the red lead of the ohm meter to the yellow, yellow/gray, then the red wire (some rectifiers may also have a fourth yellow/blue wire. If so connect to that also). Now, reverse the ohm meter leads and check those same wires again. You should get a reading in one direction, and none at all in the other direction.

Now, connect the black lead of the ohm meter to the red wire. One by one, connect the red lead of the ohm meter to the yellow, yellow/gray, and if present, the yellow/blue wire. Then reverse the leads, checking the wires again. Once more, you should get a reading in one direction and none in the other.

Note that the reading obtained from the red rectifier wire will be lower then what is obtained from the other wires.

Any deviation from the "Reading", "No Reading" as above indicates a faulty rectifier. Note that a rectifier will not tolerate reverse polarity. Simply touching the battery with the cables in the reverse order or hooking up a battery charger backwards will blow the diodes in the rectifier assy immediately

[Deershooter]

thanks for the info boatfixer I will try it out when I get home from work tonight. The wiring colors are a little different 2 yellows, 2 reds and one gray. The only one that I am not sure how to cross over from your post colors is the gray wire. Not sure what that wire is for. That wire is also only connected on one of the regulators and is plugged on the other. All that I know about that wire is that it runs up to the throttle controls throught the harness.

[boatfixer]

The gray is the tach, dont worry about that one.

[Deershooter]

thanks boatfixer I just wanted to know why there was only one that was hooked up and that makes sense. I tested both of them out last night and neither one of them ohmed out. So I am going to pick them up next week before I head up to leech. Thanks for all the help.