50Hp evinrude OVERCHARGING!!!!

[1meangreen1972]

my 50 hp 2 cyl evinrude which is a 1974 year. Is now overcharging
i noticed this the other day when i was tinkering on my gauges, they just weren't working quite right,I hooked the gauges up and started the motor and the amp gauge started reading 16v so i double checked it at the battery and yes it was indeed at 16v so then i decided to disconnect the amp gauge thinking it was hooked wrongly. nope still at the bat 16v, I know before hand this was not a problem because when I got the boat it was charging at 13.5-14v NEVER at 16.. and i'm at a complete standstill since i've read that the tach won't function right if the charging system isn't working, i also read that the rectifier could be the problem.. is there a way to test these things? I had a used one in my tool box from a previous outboard i'd had and it still does the same thing 16v at the bat... PLEASE SOMEONE HELP ME.....i'm thinking a wire somewhere is shorted and touching another hot? is there anywhere i can download a diagram for this engine?

 

[Barnacle_Bill]

Re: 50Hp evinrude OVERCHARGING!!!!

High voltage is usually caused by dirty connections, loose connections. the wrong type battery (none deep cycle) or a bad battery.

 

[D.spencer]

Re: 50Hp evinrude OVERCHARGING!!!!

take away it's credit card-ha,ha...no seriously, that is an unregulated system. The rectifier does not control the alternator output voltage, it simply converts the ac voltage to dc( split the sine wave-technical jargon). These systems were self-limiting e.g., they were typically not for carrying a lot of accessories. I would verify power and ground connections anyway at both the engine and battery ( especially ground connections- see if they are clean but don't just look at them, use your fingers and try to turn/twist to see if loose). how did you test for voltage at the battery? did you use a good quality volt meter? ( not the boats' instrument).

 

[Vic.S]

Re: 50Hp evinrude OVERCHARGING!!!!

You mean voltmeter not amp meter. Amp meters read the current flowing in amps. Voltmeters read volts.

As said that engine has a simple rectifier not a regulator and rectifier combined so a reading as high as 16 volts is not entirely unexpected once the battery is fully charged.

Do you have an ammeter fitted as well as the voltmeter if so what charging current are you getting?

The high reading pretty well proves that your stator coil is good and that the rectifier is also good. There are instructions for testing small rectifiers in the engine FAQs if you really must test it (But use a digital meter on its diode test range not a resistance range as they do not necessarily work for diode testing on the resistance ranges)

 

[1meangreen1972]

Re: 50Hp evinrude OVERCHARGING!!!!

Hey fella's
thanks for all the advice about the connections I did have a loose connection on my positive side, i just fixed that however and am still showing over 16v on both my voltmeter on the boat and a multimeter at the battery.. however i did notice that earlier when i started the boat it ran for about 5 minutes charging perfectly at 13.5v. however you all are right there is no regulator on this motor.. so my question is what regulates the volts comming out of the stator to bring it within tolerances of a 12v battery?? this is confusing me because like i said earlier this thing NEVER did this before....

 

[Barnacle_Bill]

Re: 50Hp evinrude OVERCHARGING!!!!

The battery itself does the regulating. Thats why its important to have a marine battery and not a car battery installed. Have it load tested for free at your local auto parts store.

 

[F_R]

Re: 50Hp evinrude OVERCHARGING!!!!

Never did it before makes one wonder what was wrong "before". 16 volts with a fully charged battery is perfectly normal on an unregulated system. There are thousands of them out there doing the same thing but if they don't have a voltmeter they don't know it.

 

[Vic.S]

Re: 50Hp evinrude OVERCHARGING!!!!

Thats why its important to have a marine battery and not a car battery installed

Are you suggesting that a marine battery is more able to withstand this "over" charging or more able to "control" the voltage.

Whichever, what features of the marine battery enables it to do this?

I would have though the most important point was to use a conventional flooded acid battery that can be topped up when necessary rather than a sealed battery or in particular a gel battery.

 

[Barnacle_Bill]

Re: 50Hp evinrude OVERCHARGING!!!!

Are you suggesting that a marine battery is more able to withstand this "over" charging or more able to "control" the voltage.

Whichever, what features of the marine battery enables it to do this?

I would have though the most important point was to use a conventional flooded acid battery that can be topped up when necessary rather than a sealed battery or in particular a gel battery.

This explains the differences much better than I can. http://www.outdoorsmenadventures.com/?p=154

 

[Vic.S]

Re: 50Hp evinrude OVERCHARGING!!!!

Thanks for the link. Several things in there that I don't think I have read before, but it did rather lose a bit of credibility by talking of sulfur deposits in the middle. It is of course lead sulfate that is formed on the plates as the battery is discharged and converted back into lead , lead dioxide and sulfuric acid when it is recharged. However I have added it to my growing list of sites that give info on batteries.