Alternator quit working, I need some help

[scorpio77]

Hi guys,

Yesterday while motoring, I had a broken sea water hose, It splashed salt water all over the engine, so I stopped the Yanmar 2GM20F to make a provisional repair to get to the marina, when I started the engine again, the charge light didn't went out, it remained on for the rest of the trip.
The belt and connection were in good condition,
Do you think this alternator failure could be a consequence of the salt water or just a coincidence?
I will appreciate your help before calling a mechanic, maybe i can fix the issue with your help.
Thanks in advance

Jose Luis Salgado

 

[CalebD]

You will want to measure the voltage at your batteries and alternator to confirm that your alt. is dead.
Your batteries should show about 12.3V but with the alternator charging you should see somewhere between 13.8 - 14V.
If you can't see any voltages over 13V then it is likely you may have fried a diode or two in your alternator. Take alternator to an auto repair shop that does starter motors and alternators.

 

[Warren Milberg]

Before taking off the alternator for repair I'd check all the connections in the area that got splashed to see if perhaps one or more has been shorted out or corroded. My guess is that the alternator/charge sending unit is the culprit here.

 

[Ray Bowles]

There is a spray liquid called "Electromotive" that is sold in auto parts stores. It is in an aerosol spray can. This is used to clean electrical connections and equipment, mainly 6,12,24 volt applications.
Spray it directly into the open vents at the front and rear of the alternator as it is running. It is very possible that this will clean the areas of the alt that the water could have fouled. I use it regularly for this type of cleaning problem. If no improvement then take the alt to an automotive or truck electrical shop for deeper help.
Good luck, Ray

 

[Johnb]

I had the same thing happen but with fresh water. After putting a hair dryer on it for 1/2 an hour the problem went away, so far for 5 years. If it was salt water I would have doused it with distilled water, which is electrically pretty inert. I think the "wire dryer" mentioned above is also a good idea. Nothing much to lose....

 

[sailaway78]

Look first

I would look first for a connection problem. Although thats pretty quick for any corrosion to occur. But alternators/regulators are not normally subject to damage from water intrusion, even salt water. You didn't mention whether or not you have an external regulator, but that could be a source of the problem. But look first for a connection problem, somewhere beside the alternator itself.

 

[Stu Jackson]

I agree. Connections. The "Electromotive" idea sounds very good. If something electrical doesn't work, always try the connections first. Even if they "look" good, take pictures or draw a sketch or both, take one at a time off, clean them and keep doing it.

Good luck.

 

[Bill Roosa]

I find it unlikely that both the alternator and the water leak happened at the same time for different reasons.
The salt water did something. Corrosion is going to take a while to happen so lets discount that for now. Salt water is not going to "take out a diode" in 15 minutes either but it could have shorted out a connection between two wires on the regulator circuit. As these units are sealed it pretty much has to be near or in a connection that "plugs in". A bolt on connection is not going to be effected in the short time given.
Before I did anything I'd try running the engine and see if the alternator works after setting for a while. the easy check is watch the panel volt meter before and after starting the engine (with the charger off of course) Any voltage rise would indicate that the alternator is at least working partially. If she comes up to 14.4 then you are golden and just need to check that the problem does not occur again.
If it still is not producing I'd take off the regulator plug and reinsert it and check it again.

 

[scorpio77]

Thank you all guys for your help, I'll apply all your advices before take the alt to a shop when I return to the boat, I think it was caused by the water because it was in the same moment, I'll let you know