Rectifier keeps going bad

[tjbass]

I have a 1998 90hp Johnson I have replaced the rectifier twice this year. When I put new one it works for awhile then stops charging when working it puts out up 16 volts. not sure if that's to much and burns out. any help would be great thanks

Thanks TJ

 

[ondarvr]

So do you have a crossflow or looper.

 

[jakedaawg]

^^^ that's an important question. Some are water cooled. Need model #. Other likely cause of failure is bad/old cables and wingnuts on battery. Wingnuts ruin more rectifiers than anything followed closely by corrosion, bad/old cables, loose connections, jump starting, running without battery installed ruins them instantly, asking more than you should from them (they are not.meant to charge dead batteries).

 

[tjbass]

The model # is J90tslec I did get a new battery about a month ago with new wing nuts
​Would putting to high of volts cause them harm

 

[jakedaawg]

You need to make sure the cooling system is working and the void under your regulator actually gets
water.

The tell tale peeing tells little, when did you last do an impellar?

Does your warning horn work? Have you ever gotten a tone?

Is this freshwater or salt?

I mention wing nuts because people use fingers to tighten them. They need to be replaced with star washers and nuts! It actually states this in many manuals.

So, in conclusion, you need to make sure that all connections are clean and tight, that your cables are good (hint: they are 20 years old!), that your cooling system is well maintained and not full of corrosion and salt scale, and that you are not asking the charging system to do more than standard appointments on a vessel combined with a good old fashioned lead acid flooded cell battery.

 

[gm280]

16 volts seem high for merely charging the battery. That could point to a stator output being high and toasting the rectifiers. However, voltage usually doesn't toast things, current does. It would be interesting to know how much current is flowing in the charging circuit.

Make sure your rectifier is getting the proper cooling water flow as a first thing to check. JMHO

 

[ondarvr]

For that motor 16V would be normal because there's no voltage regulator, and the rectifier is not water cooled.

​I had the same motor, I fried a couple of rectifiers, once a friend (an OMC mechanic) connected the battery terminals backwards, which is an instant fry. I didn't know why it happened a couple other times. I switched to a $5.00 Radio Shack rectifier and never replaced another one.

 

[Crosbyman]

if you can order I know RS is dying or dead but such products are easily available in electronics parts/hobby shops

https://www.radioshack.com/products/50v-bridge-rectifier


​ at $2 buy a few

 

[jakedaawg]

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