Testing rectifier? Help!

[WildWillJAX]

I have a 1989 90HP 3 Cyl Merc and a Clymer manual.
The manual does not cover the testing procedures for a 3 terminal type of rectifier. The maual shows a 4 terminal type and procedures for same.
Anyone know the test procedures for the 3 terminal type? The rectifier has a center terminal labled grey/tach, and two terminals labled alt/yellow. This type is a non grounded bakelite plastic case which is attached with two screws to the starboard side of the engine. The part has a p/n 17602 on the plastic case.
Thanks
Will

 

[Laddies]

Re: Testing rectifier? Help!

Will you are looking at a terminal board for the alt. and tach connections follow the yellow wires and you will find the rectifier it has 2 red and 2 yellows that plug in

 

[WildWillJAX]

Re: Testing rectifier? Help!

This item does not appear to be a just a terminal board but an electronic component (sealed with epoxy on the underside). I have sourced all the wires, there are two yellow wires that connect to this unit the from the stator, and two yellow wires that connect to the voltage regulator (in parrallel at the alt/yellow terminals) and a single tach wire (to the center terminal.
I cannot locate any other components in my charging system other than the voltage gauge, so I am assuming this is a rectifier of sorts.
The merury parts book does not "part number" a rectifier, so I am kinda confused about this item.

 

[Don S]

Re: Testing rectifier? Help!

You probably need to get rid of that Clymers manual, that is why you can't find the info you need. The OEM Merc manual shows how to test the several different types of 3 terminal regulator/rectifiers used during that era. Can't tell which one you have.

Might want to check ebay for a Merc service manual with part number 90-13645--2 dated 10-95

 

[Laddies]

Re: Testing rectifier? Help!

The rectifier and voltage regulator are 1 unit, if you have a regulator the rectifier is built in and a rectifier is a stand alone unit with 2 yellow 1with a gray tach wire attached to 1 of the yellow and a red wire, on a regulated system there is no where to pick up a tach signal hence the junction block before it to pick up signal for the tach

 

[WildWillJAX]

Re: Testing rectifier? Help!

Thanks, that is the answer that I was looking for.....today the boat goes out for a test run. Thanks to this forum I am anticipating a smooth running Merc again.
Thanks
Fair winds, and following seas
Will