Alternator?

[Bubba_in_ct]

I have a 1987 Celebrity with a 260HP 5.7L Mercruiser Alpha One. Well, have had a lot of rain lately and my bilge pump stuck on and ran one of my batteries completely down. I switched over to the good battery and started her up. I noticed the voltmeter on the dash was reading a hair under 13 volts. I switched over to the dead battery and it dipped to 10. Motor ran for about a minute and died. Switched back to the good one and runs fine.

My question: Is the battery drained too much to run and charge? Is the alternator bad since it isnt putting out full voltage and cant run the engine? Tomorrow (weather prevailing) I will head down with a DVM and get true voltages. Any ideas?

 

[Don S]

Re: Alternator?

Move your battery switch to both and run it for a while. Before going directly to the dead battery.
Could also be an expired battery. Your best option would be to remove it, get it charged and load tested before reinstalling. If it's over 5 years old junk it and get a new one.

 

[Bubba_in_ct]

Re: Alternator?

Thanks. I will try that. Battery is only 2 yrs old. it's the deep cycle one, so hopefully I didnt kill it.