Rectifier upgrade Mark 58

shadowrider

Petty Officer 2nd Class
Joined
Feb 19, 2009
Messages
195
I have successfully installed a 25 amp bridge rectifier on a 73' merc 850, thanks to the help from this forum. Is there any reason it would not work on my Mark 58 Mercury motor? Original is burnt up. Thanks
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: Rectifier upgrade Mark 58

The original is a selenium rectifier. Amazing it lasted this long. Sure, you can replace it with a silicone rectifier.

I found the diagram. It is a full wave rectifier, so you hook it up just like the other. Stator leads to ~, + to battery, and - to frame ground.

View attachment 13.pdf
John
 

petryshyn

Commander
Joined
Oct 3, 2001
Messages
2,851
Re: Rectifier upgrade Mark 58

Keep an eye on your battery voltage if you switch to silicone diodes. Selenium rectifiers have more internal resistance and tended to act as a poor mans regulator. The silicone rectifier will allow a higher charge voltage and may overcharge your battery and overvoltage any accessories connected...
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: Rectifier upgrade Mark 58

Keep an eye on your battery voltage if you switch to silicone diodes. Selenium rectifiers have more internal resistance and tended to act as a poor mans regulator. The silicone rectifier will allow a higher charge voltage and may overcharge your battery and overvoltage any accessories connected...

I doubt the stator will supply enough current to cause any trouble. That looks like a 3-5 amp selenium stack. Any more than that from the stator would have fried it in a heartbeat.
 

shadowrider

Petty Officer 2nd Class
Joined
Feb 19, 2009
Messages
195
Re: Rectifier upgrade Mark 58

Great, I will get er done. Thanks J-Martin for your research and specific info. Petryshyn, I will keep an eye on voltage, Thanks
 
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