Possible alternator problems???

msloan1993 · **Joined:** Thu Mar 01, 2012 11:18 am **Posts:** 3

Hello guys/gals. I'm new to the forum. We own a horizon 180 - 2006 model. I have replaced the battery recently but for some reason it continues to die. I'm guessing I have a faulty alternator. Could it possibly be something else?
The engine will crank when I jump the battery off or put a charge on it, but then it eventually dies. I want to make sure it might not be something easy that I could fix myself before taking it in for a new alternator.

EvilZ · **Posted:** Thu Mar 01, 2012 12:10 pm

Do you disconnect the battery or turn the batery selector switch (if you have one) to Off between uses? That may help determine if you have something draining the battery between uses (bilge pump stuck on, stereo, etc....).

msloan1993 · **Joined:** Thu Mar 01, 2012 11:18 am **Posts:** 3

I only have a single battery and i do not disconnect it between uses but I could certainly try it

Paul I. · **Posted:** Thu Mar 01, 2012 12:57 pm

I would add a switch no matter what, its great to have. Not only for this problem, but if you did some work on the boat you can just turn off the DC power.

Your radio (am/fm) will keep the clock and memory up. Plus, some drives will use a MerCathode, I think Volvo has there own term. Both will draw power. There use for protection against galvanic corrosion to the drive. Both draw very little, but your onboard sounder could still be on, or any thing else.

If you can, I would add a 2nd battery. If you do put in a switch, make sure that the auto side of you bilge pump is wired & fused to the battery.

Graham R · **Posted:** Thu Mar 01, 2012 5:18 pm

Regardless of the advantages of a battery switch and a second battery, before you start spending on things which may not solve your problem, I'd recommend you get the existing battery checked. Batteries do not last forever, I've had a new one fail withing 13 months (that's right, just outside the warranty period !). Also check the voltage at the battery with a proper multimeter when the engine is running ( do not trust the dash voltmeter!). If it increases over the voltage when the engine is not running then the alternator is probably OK.

The VP ACP system takes virtually no current; I can leave my boat for over a month and it doesn't drain the batteries. Something else could though; a process of elimination should find out if that is the case.

Graham

ric · **Posted:** Thu Mar 01, 2012 6:07 pm

You can also bring the alt to any auto parts store, they have a tester. They can also load test the battery.

It's either one, so get em tested. If it's the alt, save $$ and just have it rebuilt. Volvo wants $$$$$$$$$$$$$$$$ for a $60 GM alternator with some screen on it.

msloan1993 · **Joined:** Thu Mar 01, 2012 11:18 am **Posts:** 3

I've actually got the mercruiser, not the Volvo. I appreciate all these helpful pointers.

ric · **Posted:** Thu Mar 01, 2012 7:49 pm

msloan1993 wrote:

I've actually got the mercruiser, not the Volvo. I appreciate all these helpful pointers.

You've actually got a Chevrolet as far as the engine is concerned. Both VP and MC use the same engine. If you're handy with a wrench and the alternator is actually bad, you can just get a new one from the right chevy car (easy to find out) for 1/4 the price of the "marine" alternator... and swap cases from the bad one to the new one. The "ignition proof" is just a metal screen attached to the back of the case. The car alternator doesn't have one.

And yes, it is 100 percent legal and USCG approved as "ignition proof" if you install the marine screen to an "automotive" alternator.

Aussie_Horizon_190 · **Posted:** Thu Mar 01, 2012 8:04 pm

More than likely just the regulator and not the alternator itself. Regulator should just unscrew and be a fairly simple replacement from most auto shops.

Paul I. · **Posted:** Thu Mar 01, 2012 8:31 pm

I forgot to mention...... I my be wrong, but the other way you can test the ALT is to do a volatge check. It should be outputing about 14.1 to 14.5 volts off the of my head. Seloc puts out very good manuals on how to test thing just like this. The 30 to $35 is worth it!!

ric · **Posted:** Thu Mar 01, 2012 9:17 pm

The easiest thing is.. what's the voltage gauge read when the engine is running? 12-13 volts.. alt going bad. Under 12 volts, it's not even working.

alanurt · **Posted:** Sat Mar 03, 2012 7:11 am

If the motor shuts off after a jump of a dead battery, it's not getting juice and likely the alternator (you indicate a new battery). Try charging the battery overnight with a charger instead of just jumping it and then start it. You should get substantially more running time before it shuts off; then you'll know you're on the right track. I had a problem with mine not charging during long runs. It would charge at the slip (charger) and always start, but if I ran it for a while, shut it off for a swim, it wouldn't start. I had to switch to all three batteries to start it. I pulled the alternator, had it tested and it was fine. The guy at the shop noticed black dust all over it. It turns out the belt was worn to the point that it would slip at high RMP's (long cruise) but would be ok if I was just bopping around on short trips with plenty of ideling. I re-installed the original alternator, replaced the belt and problem solved.

Walt · **Posted:** Sat Mar 03, 2012 10:03 am

I should hope everyone here has one of these by now. You can easily test the batt and alt separately, while still in the car/boat. However, always good to double check at the automart too.

I test each of my items seasonally. It's helped me identify a troublesome battery in the boat, and car (both about 5 yrs old) before they left me stranded.

ric · **Posted:** Sat Mar 03, 2012 9:38 pm

I have the VDO gauge problem... (and they're not the digital dash) where my gauges read just about anything they want. Key on, boat off = 10v, boat on...12.5 volts.

In reality... 12.x off, 13.6 on.

Stupid gauges.

qweedqwag · **Joined:** Mon Aug 24, 2009 9:26 pm **Posts:** 163

ALTERNATOR VOLTAGE TESTS:

1. Set Voltmeter to DC Volts (20V scale), and connect the DC Voltmeter test leads to the battery post (Red lead to Positive Post, and Black(or Yellow) to Negative). With engine “off”, read and note battery voltage (see “Battery Testing”).

2. Start the engine, and at “Idle” RPM, check the voltmeter reading. At very low speeds the alternator output may be lower than the regulator setting; hence you will expect to read the battery voltage.

3. Increase engine RPM, and note increasing voltage reading to a maximum of about 14.2 volts (12V Nominal System - expect ± 29.5V in 24V system).

If no voltage increase noted, you likely have a bad voltage regulator, or poor wiring
(Alt’ to Batt.). Go on to test 3B.

If Voltage increases go on to test 4.

3B. With engine “off”, connect Positive test lead to Alternator Output (“B+”, or “A”), and Negative Lead to the Negative Ground Post (“Neg”, or “E”) of Alternator. Start engine. If Voltage increases with increased RPM, your regulator is OK, and the problem is in the wiring. Go on to test 3C.

3C. Discharge the Battery to less than 12.5 Volts. Check for Voltage drop between the Alternator and Battery, as follows..
Connect the Positive Test Lead to the Alternator Positive Output Terminal (B+) and the Negative Lead to the Positive Battery Post. Crank the engine, and increase RPM to a fast idle. Observe Voltage. If the voltage climbs to as much as 0.02 Volts (or more), the positive cable has a high resistance. Repair or replace cable.

Check for voltage drop in the negative cable, as above - but: connect the Positive Lead to the Alternator’s Negative Output Terminal, and the Negative Lead to the Negative Battery Post. Analyze as above.

MIke

www.iFourWinns.com

Possible alternator problems???

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