1986 305 i/o alternator

[davey buoy]

Hi guys,what would make a alternator stop charging in a instant?.Here's what happened.Last Saturday starter just clicked.Found loose negative terminal,tightened,volt gauge went to 13.9/14 volts. Next day did a check of both batteries and terminals.Started boat up,checked voltage while running ,close to 14 volts on each battery.Out on the boat this afternoon and gauge on boat reads about 11volts or so.Started well all afternoon.

Arrived at home ,fired it up,check voltage with my meter,only 12.3 volts while running and boat gauge reading slightly lower than that.

Belt is tight,no noise.Wandering if there is a fuse or reset for the alternator. Hard to believe from point A to B on trailer, alternator just stopped charging.Any help or ideas would be really appreciated.

Edited July 22, 2012 by davey buoy

[Woodsman]

Could be the voltage regulator giving up.

[Muskieman]

Yep on the VR ....

[davey buoy]

On the GM alternators is the voltage regulator inside the casing or external?. thanks.

[Muskieman]

1986 = external .... Usually ...

[Muskieman]

Do you have a fan on the alternator ?

[davey buoy]

Do you have a fan on the alternator ?

Yes it does right behind the pulley.

[Muskieman]

External for sure , follow the wires to the regulator ...

[davey buoy]

External for sure , follow the wires to the regulator ...

 

Thanks Randy,I'll look for it tomorrow.

[ecmilley]

many gm alternators in that year and even my 81 z28 had a internal regulator, small square plug on the alt is usually external reg and a small flat rectangular plug is usually internal.

for the internal its easy to check turn key on and there should be power at the fields and sensing wires, if you have voltage the alterntor is done.

you could always try tapping it with a hammer may be sticking brushes as well

[davey buoy]

many gm alternators in that year and even my 81 z28 had a internal regulator, small square plug on the alt is usually external reg and a small flat rectangular plug is usually internal.

for the internal its easy to check turn key on and there should be power at the fields and sensing wires, if you have voltage the alterntor is done.

you could always try tapping it with a hammer may be sticking brushes as well

 

I will try a light tap today as well as the plug shape,to see if it is a internal or external voltage regulator. Thanks.

[davey buoy]

Here is a couple pictures of the alternator,hope this will shed some light as to if the voltage regulator is internal or external.Thanks.

[davey buoy]

The wires that come from the alternator join a large taped bunch of wires and possibly go to this part on the opposite side of the motor just above the fuel filter. Could this be the voltage regulator beside the circuit breaker button?Here's a picture of what I'm trying to explain.

Edited July 22, 2012 by davey buoy

[misfish]

Davey

 

If you want it to be rebuilt,take it to

 

http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&ved=0CGUQFjAF&url=http%3A%2F%2Fwww.canpages.ca%2Fpage%2FON%2Fbarrie%2Ffoxcraft-alternators-and-starters-inc%2F3568665.html&ei=kD8MUJ-6OMbw0gHyt8zhAw&usg=AFQjCNHrR37xpr6EbYr1j5v38X67QpPTZQ&sig2=S7lFx549t1M_O-F074X0Iw

[davey buoy]

Davey

 

If you want it to be rebuilt,take it to

 

http://www.google.ca...9t1M_O-F074X0Iw

 

Thanks Brian,but I'm still trying to determine if the voltage regulator is internal or external before I remove it.

[ecmilley]

i can't see it well enough but it does look like a old internal regulated alternator. see if there is voltage on thos teo wires with the unsealed crimp connectors, marine use and unsealed wires is asking for trouble

[davey buoy]

i can't see it well enough but it does look like a old internal regulated alternator. see if there is voltage on thos teo wires with the unsealed crimp connectors, marine use and unsealed wires is asking for trouble

 

The bullet connectors?. When running I would assume?. Another thing I noticed if of any help,when I turned of the battery's switch to" off" the boat stopped immediately .It has #1, both ,#2 and off.

Edited July 22, 2012 by davey buoy

[davey buoy]

Just talked to a back yard marine mechanic I know and said if there is a cap on the back of the alternator,attached by 4 phillips screws,under that is the regulator. Should have two wired bullet connectors and a ring connector to the casting outside the cover.Well it looks like that's mine. I'll take it off the back tomorrow and see what happens. May not have to remove the alternator.What do you think?. Possible?.

Edited July 22, 2012 by davey buoy

[Tybo]

myself would pull it out and take to a shop to get it bench tested.

I changed the alt in the truck this just because it was 10 years old.

A stitch in time saves nine.

[davey buoy]

myself would pull it out and take to a shop to get it bench tested.

I changed the alt in the truck this just because it was 10 years old.

A stitch in time saves nine.

 

Taking your advise Paul,it's out and dropping it off tomorrow at Brian's recommended shop to see what's going on.Thanks guys.