My Mercruiser 140 I/O is draining the battery

[waterstrider09]

I have an 84 mercruiser 140 181 cid that is draining the battery. I don't think it has a voltage regulator. I replaced the alternator, checked all the wiring, everything on the boat works, but after a day or two on the lake the battery is depleted. I replaced the gauge and it still reads only at 8-10, not 12-14. I ran it without using any extras all weekend and still runs down...HELP.

 

[bruceb58]

Re: My Mercruiser 140 I/O is draining the battery

Get as multimeter that measures current.

1) Take off one battery cable and measure your current draw. Then replace the cable.

2) Take out a fuse one at a time and measure across each spot where you took out the fuse with the ammeter to determine which circuit may be your problem.

3) Take off the output of the alternator and measure to see if the alternator is drawing current.

Do all of these with the key off.

 

[Bondo]

Re: My Mercruiser 140 I/O is draining the battery

I replaced the gauge and it still reads only at 8-10, not 12-14. I ran it without using any extras all weekend and still runs down

Ayuh,... Replaced Alternator or not,... It's just Not Charging...
Grab a multimeter,+ Follow the Power...


Bruce,... I misread it as well,+ was going to ask if the boat leaked,+ had an auto-bilgepump,...
He's talking Runnin' it for 2 days,+ killin' the battery...

 

[bruceb58]

Re: My Mercruiser 140 I/O is draining the battery

Bondo, yes..I see that now as well.

 

[waterstrider09]

Re: My Mercruiser 140 I/O is draining the battery

No i dont have a leak or an auto bilge pump. It's draining it like i left the dome light on. It doesn't have a dome light, nor can i figure out what may be drawing current. I'll try buying a meter though, good idea. That's my next move before redoing the wiring completely. Its' an 84 so the wiring is iffy in spots...