Alternator help

Joined
Sep 19, 2012
Messages
17
I have a 1982 OMC 140. My alternator is only putting out 8 volts. What should I check? What could be limiting it? Dave
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Where are you measuring? Using a hand held voltmeter, place the probes on the battery terminal itself -- not the cable clamps. Take a reading with the engine off, then start the engine and at 1500 - 1700 rpm the reading should increase. Static battery voltage is 12.6 volts. With a functioning alternator voltage should rise to 13.5 - 14.5 volts. Dirty or corroded battery cables can mask charging problems. Clean the terminals and connections at both ends of each cable. If none of this corrects the issue, take the alternator to any auto store and have it tested -- normally for free. Any alternator shop in town can likely rebuild the unit much cheaper than a new alternator.
 
Joined
Sep 19, 2012
Messages
17
Thanks for the reply. I am getting 11.8 @ the battery & 8.6 or so on the back of the alternator. I am foibg to pull the alternator & the regulator after this trip.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
I hope you take another fully charged battery with you. 11.8 volts at the battery is an indication it is already discharged and you will likely be stranded. The engine ignition system requires power to operate. That power is coming from a battery that is not being charged. 8 volts at the alternator is doing nothing for you.
 
Joined
Sep 19, 2012
Messages
17
Well, finally got the alternator tested and it is in fact dead. New one is on the way. Thanks for the help folks...

Dave
 
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