90hp rectifier conversion / swap out?

[Hess]

I?ve got a new-to-me ?93 90hp Evinrude with the tach not working and the battery not charging. Done a lot of searching and found this fine forum? and have read / searched it over as well, and done some of the tests (now I?m dangerous). Through all this, I?ve learned that it?s very likely I?ve got a fried regulator / rectifier which is a water cooled unit (part # 584204). So, I?m looking to replace it which brought on several more questions about removing the flywheel (also researched).

In another post from years ago here (Re: 85 Evinrude 115hp, Rectifier / Regulator Question “No Purple Wire”), it was eluded to that I may be able to ?cut the wires? and wire in a ?standard? rectifier. Is this an option? If so, I have a bunch of questions:

1) What rectifier would I order to wire in? I?ve concluded I have the 3/9 amp stator (#583586) as I have P/T/T.
2) Which wires would be cut to splice in the replacement / where would it need to go in regard to the wiring?
3) Is it possible to differentiate / confirm that the regulator is OK and rectifier is not? How to?

Adding a ?standard? rectifier would really make the job much easier, cheaper, and eliminate the poor design which seems to fail often (and possible cause a fire). By the way, I just replaced the water pump which was probably the root of the failure from the previous owner.

4) I also noticed discussions on the stator being fried as a result of the regulator / rectifier failing. Is there a way to check / verify this prior to digging in?
5) If I do have to ?dig in?, after flywheel removal is it self explanatory as to replacing the original regulator assembly? Any ?adjustments? to be concerned with?

Thanks in advance for any information to any of the many questions I am asking. I?ve got a Clymers manual but it?s very weak for all this (it was weak for the water pump as well!).

 

[ezeke]

Re: 90hp rectifier conversion / swap out?

Yes, you can use an unregulated rectifier. You need to be aware that there are some battery issues, but the unit wires to the terminal block, so it is easy to do.

http://www.iboats.com/Cdi_Rectifier...67626582--list_time.1179245524--view_id.47460

If you go to the parts catalog for your motor at the BRP site and look at the ignition diagram, you will see the unregulated rectifier as #66 in the diagram. I believe it was standard on the 88HP commercial model.

http://epc.brp.com/default.aspx?brands=ej&lang=e

 

[Hess]

Re: 90hp rectifier conversion / swap out?

Fantastic and thanks for the part reference. Your words "Unregulated Rectifier" explained a lot to me.

What do you mean by "some battery issues"? The possibilty of "over charging" due to it being unregulated?

Would I cut / remove ALL of the existing wires from the existing rectifer / regulator and wire this into the 2 yellows and 1 red?

Another thought / question... will this process revive my tach?

 

[ezeke]

Re: 90hp rectifier conversion / swap out?

There is a bit of disagreement on why there is a problem, but generally everyone agrees that if you have a large enough battery it can take the charge and regulate it enough. Personally I use large dual purpose deep cycle marine batteries, so I have no issue, and therefore, little personal experience.

The guys who try to use maintenance free auto batteries almost always have the high voltage showing. Sometimes that voltage is too much for things like fishfinders and depth guages, I am told.

Some marine batteries' literature recommends that you not use unregulated chargers on their batteries - such as the ones sold here at iboats:

http://www.iboats.com/Optima_Marine...67626582--list_time.1179248664--view_id.52134

There is always a possibility of further damage whenever a rectifier goes bad because occasionally the heat fuses the wiring within the rectifier and allows the battery's full power to flow through the rectifier to components beyond it. The diodes are there to prevent that and usually they just burn out an do not allow current to flow either way.

The regulating function in a regulated rectifier generates considerably more heat, which is why they need to be water cooled. It is also another reason why keeping the water pump in excellent condition is critical.

You may be able to get a activity on your tach now by disconnecting the gray wire from the rectifier to the terminal block and connecting the gray wire from the main control harness to the gray and yellow alternator wire on the terminal block.

 

[Hess]

Re: 90hp rectifier conversion / swap out?

Ezeke, you've been extremely helpful and I sincerely appreciate the time / discussion you've provided.

Can you tell me though, how to actually wire this in? Do I disconnect ALL of the existing rectifier / regulator wires and patch in the new rectifier into the terminal block??? Looks like 2 yellows and one red in the picture, so I'd assume they would simply go to the same (?).

I've got a standard Sears Die-Hard Marine starting battery and the boat is a small lake runabout with no electronics asside from a cheap finder... that I'll replace sometime soon.

Thanks again.
Hess

 

[ezeke]

Re: 90hp rectifier conversion / swap out?

The ground for the newer rectifiers is the case bolted to the engine so they eliminated the older model's forth wire.

The red wire connects to the terminal block screw with the red wire running to the battery.

If the yellow wires on the rectifier are the same color [no gray stripe] they can connect in either order to the screws on the terminal block with the yellow and yellow and gray wires from the alternator.

Connect the gray wire from the main harness to the yellow and gray wire from the alternator.

Do not do any of this with the battery connected.