I think my alternator's shot, based on the tests I've done, but I'm
still running around the lake with no problem. . . . . yet!

Boat's got a '78 5.7litre Mercruiser with a two-bank, four battery
system. Batteries are two week's new, basic crankin' batteries. I've
had it out four times, with about 8 total running hours. Bank 2, the
only one I've used, is reading about 12.2v on one of the on-boat
meters, bank 1 shows about 12.8v. Alternator tester showed similar
numbers, and no increase in voltage when engine was running. Ammeter
on flying bridge shows 0 - no draw or charge, other meter (don't
remember if volt or amps) shows in red, discharge state for both banks
when running.

I'm taking the alternator to the shop on Monday, but I'm wondering if
this is unusual. Should I be able to run around this long on a
two-battery bank with what appears to be a shot alternator?

Thanks,
Speedo

You're living on borrowed amperage.

Much more of a drop in your battery readings, and your ignition system will
come to a sputtering halt. Every time you start the boat, you're using up power
that you would need to stary running.

IMO, heave to until you get your alternator fixed, rebuilt, or replaced.






http://www.publicdebt.treas.gov/opd/opdpenny.htm

I'm taking the alternator to the shop on Monday, but I'm wondering if
this is unusual. Should I be able to run around this long on a
two-battery bank with what appears to be a shot alternator

If you put it on a charger when you get home and don't run a trolling motor it
will run forever.

I don't think very long if u use the trim tabs and motor trim much and
starting all high amp draw, I broke a belt one day and was putting the trim
up and the motor died, lucky for 2 batteries and running on one. get a
rebuild for peace of mind. GL

"Gfretwell" wrote in message
...
I'm taking the alternator to the shop on Monday, but I'm wondering if
this is unusual. Should I be able to run around this long on a
two-battery bank with what appears to be a shot alternator

If you put it on a charger when you get home and don't run a trolling
motor it
will run forever.

If you have group 27 batteries, I don't see why not. 4 of them make
quite a store house. I have run an entire "female friendly" cabin
cruiser, overnight, on one battery and it had plenty left.

Capt Frank

speedo wrote:

I think my alternator's shot, based on the tests I've done, but I'm
still running around the lake with no problem. . . . . yet!

Boat's got a '78 5.7litre Mercruiser with a two-bank, four battery
system. Batteries are two week's new, basic crankin' batteries. I've
had it out four times, with about 8 total running hours. Bank 2, the
only one I've used, is reading about 12.2v on one of the on-boat
meters, bank 1 shows about 12.8v. Alternator tester showed similar
numbers, and no increase in voltage when engine was running. Ammeter
on flying bridge shows 0 - no draw or charge, other meter (don't
remember if volt or amps) shows in red, discharge state for both banks
when running.

I'm taking the alternator to the shop on Monday, but I'm wondering if
this is unusual. Should I be able to run around this long on a
two-battery bank with what appears to be a shot alternator?

Thanks,
Speedo

Get the altenator fixed, you're not doing your batteries any favours.


"speedo" wrote in message
om...
I think my alternator's shot, based on the tests I've done, but I'm
still running around the lake with no problem. . . . . yet!

Boat's got a '78 5.7litre Mercruiser with a two-bank, four battery
system. Batteries are two week's new, basic crankin' batteries. I've
had it out four times, with about 8 total running hours. Bank 2, the
only one I've used, is reading about 12.2v on one of the on-boat
meters, bank 1 shows about 12.8v. Alternator tester showed similar
numbers, and no increase in voltage when engine was running. Ammeter
on flying bridge shows 0 - no draw or charge, other meter (don't
remember if volt or amps) shows in red, discharge state for both banks
when running.

I'm taking the alternator to the shop on Monday, but I'm wondering if
this is unusual. Should I be able to run around this long on a
two-battery bank with what appears to be a shot alternator?

Thanks,
Speedo

alternator may be charging very little or it could just be the voltage reg.
how old it the alt.? my belt just broke on a 5.8 l omc and my motor ran
terrible on startup and almost died getting away from the dock. if the reg.
is in the alt. I would just replace the whole thing especially if its fairly
old. And do it right away, I would hate to get towed in, that is my
definition of a bummer. GL
"Brian Runyard" wrote in message
...
Get the altenator fixed, you're not doing your batteries any favours.


"speedo" wrote in message
om...
I think my alternator's shot, based on the tests I've done, but I'm
still running around the lake with no problem. . . . . yet!

Boat's got a '78 5.7litre Mercruiser with a two-bank, four battery
system. Batteries are two week's new, basic crankin' batteries. I've
had it out four times, with about 8 total running hours. Bank 2, the
only one I've used, is reading about 12.2v on one of the on-boat
meters, bank 1 shows about 12.8v. Alternator tester showed similar
numbers, and no increase in voltage when engine was running. Ammeter
on flying bridge shows 0 - no draw or charge, other meter (don't
remember if volt or amps) shows in red, discharge state for both banks
when running.

I'm taking the alternator to the shop on Monday, but I'm wondering if
this is unusual. Should I be able to run around this long on a
two-battery bank with what appears to be a shot alternator?

Thanks,
Speedo