CONTINUOUSWAVE

Gentleman--I have a 1983 Johnson 70-HP outboard engine [whose alternator] is putting out [a charging output of] upwards of 17-volts [when the engine is] running fast.

Do readers have experience with the CDI 193-3408 regulated rectifier?

I would like to try it, but I've had a bad experience not using factory parts.

I suspect that the CDI part is an aftermarket part that improves the charging output by adding voltage regulation. If there is no equivalent OEM upgraded part, I don't see that there is much concern for getting an aftermarket part from CDI. CDI seems to be making a better-than-OEM part in many cases.

On a 1989 Johnson 70-HP engine I owned, I replaced a defective rectifier with one from CDI, and it worked fine. But, if you are seeing high voltage on yours, you first may want to look into the condition of the battery and connections. Since this is an unregulated system, using only a rectifier, it requires a battery that is in top condition to maintain reasonable voltage levels. Otherwise, if the battery is not holding a proper charge, is the wrong capacity, or just old, the system will reach higher voltages in an attempt to recharge the battery.

I do see that the rectifier you are thinking of buying now comes with a built-in regulator. That sounds like a good idea, but the standard rectifier system should work fine if everything else is up to par. Looks like that new rectifier is also about three-times the cost of a standard one.

Relying on the battery to act as a voltage regulator was an acceptable strategy for designing an outboard engine in 1940, but it makes no sense today. The added cost of buying a regulator as part of the replacement part is negligible. Unregulated charging outputs can cause many problems. See

http://www.cdielectronics.com/blog/regulated-rectifier/