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#568144 - 06/13/17 05:02 PM Alternator question Volvo 4.3fi
jec6 Offline
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Registered: 01/14/15
Posts: 29
Loc: South East PA / Keuka Lake
Hi All,

I haven't posted in a little while, but I still stop in here often and read up on boating wisdom.

I had my 2008 Regal 1900 out this weekend and after a few minutes of idling around teaching my wife how to pull up to docks, we had a low voltage warning. When I shut the boat down, it wouldn't restart. I picked up a new battery and installed it. Everything started up fine, but the Voltmeter gauge was showing about 12 1/2 volts. I grabbed my multimeter and read the battery terminal voltage with the boat off - 12.4 volts. I started it up and got 12.4 volts. I checked the terminals at the back of the alternator and got 12.8v, not the 13.9 - 14.2 that I'd expect. With the engine running, I swtiched off the battery kill switch and it kept idling fine. I *assume* this suggests the alternator is failing but not completely dead. Engine is a Volvo Penta 4.3Fi (Gxi)

I have a few questions:
1. Am I missing anything? Is there anything else I should check before replacing the alternator?

2. Is there a DIY procedure for properly tensioning the auxiliary belt that anyone is familiar with? The alternator is mounted on top of the engine and looks dead simple from a DIY perspective, I just want to be sure I get the belt properly tensioned when I am buttoning everything back up.

3. Should I go OEM Valeo a +$180 over aftermarket? If you've had luck w/ aftermarket what brand do you recommend?

Thanks in advance.

Josh


Edited by jec6 (06/13/17 05:22 PM)

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#568148 - 06/13/17 06:48 PM Re: Alternator question Volvo 4.3fi [Re: jec6]
Jack T Offline
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Registered: 01/10/03
Posts: 3602
Loc: Southern California
Can't give too much advice except to remind you that marine alternators have special spark arrestors to reduce ignition of vapors in the engine compartment.
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#568150 - 06/13/17 09:48 PM Re: Alternator question Volvo 4.3fi [Re: jec6]
kdl Offline
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Registered: 04/16/06
Posts: 2564
Loc: Central Mass
If I'm not mistaken, disconnecting the battery from a running engine is a bad idea.
Good luck on the repair. Let us know how you make out.
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#568152 - 06/13/17 09:55 PM Re: Alternator question Volvo 4.3fi [Re: jec6]
Lowrider78 Offline
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Registered: 01/31/04
Posts: 1832
Loc: Newton Ks
A circuit breaker someplace near the back of the engine that is in the alternator lead to charge the battery.

Disconnecting the + battery cable is a long-time "quick and dirty" test to see if the alternator is putting out voltage.

Today, as cheap as Voltmeters are (and some are simply "plug into power outlet/cigarette lighter") there is little use to test that way.

If charging voltage (battery voltage with the engine running) is below 13 volts, the alternator is not charging.

If it is over 14 volts, it is overcharging and can wreck a battery in short order (literally boil it dry).
_________________________
That streak that howled by? That was me. Did ya like the roostertail? Big Blocks and Jets Forever
1978 Hawiian 20' Bowrider, 454, Dominator pump
1990 Magnum Mach 1 24' Cuddy Cabin Cruiser, 454, Bravo 1 drive.
1993 Suburban 454 tows the Mach 1 to water.
2001 Blazer 4x4 4.3L gets the Hawaiian wet.

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#568154 - 06/13/17 11:40 PM Re: Alternator question Volvo 4.3fi [Re: jec6]
captkevin Offline
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Registered: 10/02/03
Posts: 6988
Loc: Chicago, IL
Might want to see if you could find a local alternator shop that could repair existing unit.
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#568155 - 06/13/17 11:46 PM Re: Alternator question Volvo 4.3fi [Re: jec6]
casualboater Offline
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Registered: 01/14/04
Posts: 3094
Loc: Highland, Michigan
I have a 'self exciting' alternator, I think that's what it's called. Anyway, doesn't kick in the volts until the RPM's go up a bit, after that it's good to go. I almost always rev it a bit in neutral to see the volt meter kick up before I put it in gear, especially if I've got a no-wake zone in front of me.

If that's not your deal, I second the reman shop. They usually don't take that long and it's a fair bit cheaper then a new one. Place I took mine had one ready to go and took mine as a core and sold me the new one at the rebuild price.
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#568157 - 06/14/17 09:19 AM Re: Alternator question Volvo 4.3fi [Re: jec6]
captkevin Offline
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Registered: 10/02/03
Posts: 6988
Loc: Chicago, IL
Would think you would end up with better quality at a local shop.
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#568161 - 06/14/17 10:27 AM Re: Alternator question Volvo 4.3fi [Re: jec6]
Dave R Offline
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Registered: 07/30/03
Posts: 6444
Loc: Raymond NH
Assuming the alternator is indeed faulty, do not replace it unless you have no choice. Just replace the brushes in it. They are the only true wear item in an alternator and they are usually very cheap and very easy to swap. You may have to do a little investigation to figure out who made the alternator (probably a Valeo) and what model it is, but once you know, you can probably get a set of brushes for less than 35 bucks.

Here's a video: https://www.youtube.com/watch?v=aVvPzwtxdrM
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#568166 - 06/14/17 06:33 PM Re: Alternator question Volvo 4.3fi [Re: jec6]
jec6 Offline
Ensign

Registered: 01/14/15
Posts: 29
Loc: South East PA / Keuka Lake
Thanks for the info.

When I did the multimeter check, I did not understand why I'd see 12.8 at the Alternator with some +/- voltage fluctuation compared to the 12.4 on the newly installed battery. I expected that if the alternator was truly failed it would show 12.4 or less since the battery was the sole power source and some system resistance would show a minor voltage drop at the alternator poles. I did rev the engine to see if there was a voltage increase above 2k rpm, but there was not (there was some minor voltage fluctuation up and down but nothing steady state).

That is why I (wrongly in hindsight) switched off the battery switch, I wanted to see if the Alternator was indeed providing power to keep the engine running. I (wrongly) assumed if the alternator wasn't providing power, the engine would stall out when I switched off the battery kill switch.

Live and learn, hopefully without too much $$$ lost.

Lowrider: Do yuo have any more info on the circuit breaker on the backside of the engine in line with the alternator? I could not find any info in my owners manual about that. Does it exist on all GXi engines and where would I find it?

Input I have received is 100% go with a marine rated alternator. Does anyone have input on brand preference? My current is a Valeo 3884950

So, based on all the feedback, Alternator is highly likely the culprit. Does anyone know of a DIY for replacement (want to get directions on belt tensioning).

One issue is the boat stays on a lift at our lake cottage, and we're only there weekends & holidays. I don't have a lot of spare time to tinker with it. Next time we're there will be 4th of July weekend and I'm going to get a lot of pressure from the family to wake up early, get it fixed and have it ready to float by breakfast time. It looks like I can get a Valeo replacement unit for about $170, which isn't bad. I'll keep the old one and bring it home and check the brushes, etc and keep it as a spare. If I'm missing anything, please let me know.

Thanks,

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#568167 - 06/14/17 08:53 PM Re: Alternator question Volvo 4.3fi [Re: jec6]
Silverbullet Offline
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Registered: 06/15/04
Posts: 8729
Loc: Boise, ID
Alternator should be about as easy as it gets. Release belt tensioner which should be spring loaded. Remove alternator bolts. Remove wires. Put wires on new alternator lugs. Bolt new alternator in same place. Put belt back on.
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2002 Cobalt 226 VP 8.1GIDP
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#568172 - 06/15/17 07:12 AM Re: Alternator question Volvo 4.3fi [Re: jec6]
Dave R Offline
Admiral

Registered: 07/30/03
Posts: 6444
Loc: Raymond NH
Originally Posted By: jec6


One issue is the boat stays on a lift at our lake cottage, and we're only there weekends & holidays. I don't have a lot of spare time to tinker with it. Next time we're there will be 4th of July weekend and I'm going to get a lot of pressure from the family to wake up early, get it fixed and have it ready to float by breakfast time. It looks like I can get a Valeo replacement unit for about $170, which isn't bad. I'll keep the old one and bring it home and check the brushes, etc and keep it as a spare. If I'm missing anything, please let me know.

Thanks,


That is exactly what I would do in your situation. The reason you saw something between 12.4 and 14.4 volts was because the brushes don't fail completely all at once, they degrade over time and can't provide all the needed current to excite the rotor coils.
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#568176 - 06/15/17 10:45 AM Re: Alternator question Volvo 4.3fi [Re: jec6]
Just Bob Offline
Cap'n of all things wet
Admiral

Registered: 03/08/06
Posts: 2012
Loc: Chalfont, PA
Remove the old one and take it to a local Pep Boys. They can test it for you. It'll take about 10 minutes to remove it. If it's bad, get a new one, they're only about $150. 10 minutes and you're back on the water.
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#568177 - 06/15/17 11:32 AM Re: Alternator question Volvo 4.3fi [Re: Just Bob]
Dave R Offline
Admiral

Registered: 07/30/03
Posts: 6444
Loc: Raymond NH
Originally Posted By: Just Bob
Remove the old one and take it to a local Pep Boys. They can test it for you. It'll take about 10 minutes to remove it. If it's bad, get a new one, they're only about $150. 10 minutes and you're back on the water.


Just make sure it's a marine alternator. Car alternators are not spark shielded.
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#568216 - 06/20/17 01:26 AM Re: Alternator question Volvo 4.3fi [Re: jec6]
Lowrider78 Offline
Admiral

Registered: 01/31/04
Posts: 1832
Loc: Newton Ks
IF you have one, rear top of the engine where there is usually a wiring buss strip, the breaker on one end, same side the alternator is on probably, a push-button type, probably 40 or 50 amps.



It would be in the alternator output wire (8 or 10 gauge red from the alt. to the battery).


Dad's Taylor had one @ 35 amps, when the old alt. was replaced with a newer, larger, 1-wire alternator, if the battery was very low at all, it would trip from the alternator charging the battery for a while. I had to up-size that too.
_________________________
That streak that howled by? That was me. Did ya like the roostertail? Big Blocks and Jets Forever
1978 Hawiian 20' Bowrider, 454, Dominator pump
1990 Magnum Mach 1 24' Cuddy Cabin Cruiser, 454, Bravo 1 drive.
1993 Suburban 454 tows the Mach 1 to water.
2001 Blazer 4x4 4.3L gets the Hawaiian wet.

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#568253 - 06/22/17 03:23 PM Re: Alternator question Volvo 4.3fi [Re: jec6]
Frantically Relaxing Offline
Admiral

Registered: 02/07/03
Posts: 11598
IF you have more than one battery AND a battery isolator or combiner, it could be bad-- had that problem with the Chap..
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1988 SkipperLiner 53x14
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