2006 MERCURY 225 OPTIMAX ALARM ????

[gaf11]

<1B241981>
On Saturday I was fishing a tournament and had an issue with a warning horn coming on my 2006 225 Optimax. Motor has 226 hours and I just purchased it on a Ranger Z21 boat. The horn would come on a brief second when I hit the trim button and held it down after the motor was all the way down. Let go of the trim switch and it stopped. This happened about 4 times over the past 2 trips. I have a 1000 CCA Interstate battery for the motor and it's 30 days old. As I was headed back to the launch ramp ( about 4 miles away) The horn started sounding continually. The Guardian monitor gauge had a bell and engine symbol with a VOLT emblem also flashing. It said 11.2 to 11.6 volts. My Helix 12 also said 11.2 volts. If I backed off the engine from about 4500 RPM to 2500 RPM the alarm would stop for about 10 seconds and then go to a continuous beep. I stopped the engine and checked my battery connections and they were very tight. I did find, however that the battery reset box( Red cable to battery and the other side of box to engine starter) was very loose. The cable nut, closest to battery could be moved by my fingers easily. I tightened the nut with a wrench tight. The alarm still showed on the Guardian gauge and the horn stayed on continuous. Battery voltage stayed at 11.2. I charged the battery when I got home and it's at 12.6 volts when I checked it 2 times today(not hooked up to a charger). My question...could the very loose cable cause this alarm due to the battery being drained down? I had 4 depth finders running for 7 hours and live well pumps also. Motor seemed to crank fine. Didn't lug down when starting. Trim worked fine also. I didn't get a chance to take it out today after charging the batteries. This was the 5th time I've had the boat out since buying it a couple months ago. This was the first time its done this, except it did do the alarm deal sometimes when I hit the trim button after the engine was in the full down position a second or so. Any ideas on this? Thanks again

[JOE54]

yes sir very possible

[SilverFox579]

Best double check your battery specifications...think you'll find your battery has 1000 cranking amps not cold cranking amps.

[EuropeanAM]

Best double check your battery specifications...think you'll find your battery has 1000 cranking amps not cold cranking amps.

+1

Also- what’s the engine serial number?

[gaf11]

Serial # 1B241981

[gaf11]

Don, I went and ran the various tests you've recommended. Here's what I found so far trying to figure out what my issue is on the charging system on my Optimax:

1. Battery voltage after charging- 12.8 volts
2. Engine key off. Checked volts at large red wire on alternator- 24.4 volts and the voltage was climbing from 12.6 to 24.4
3. Engine turned to on but not running red post on back of alternator(large wire) 12.3 volts
4. Checked continuity from the large red wire on alternator to post on starter solenoid- key turned off (used the beep function where an alarm sounds if continuity is available) I had no beep at all. Took the wire off the 2 posts and checked again...no alarm. Checked from the 2 wires where they meet in the middle and you have a fuse . I assume... I had continuity up to the fuse on both sides but not accross the fuse it appeared.
5. Voltage at the 2 small wires on back of the alternator- small red wire 12.53 volts small purple wire 12.41 volts.
6. Volts at battery after engine ran 5 minutes was 12.28 volts at battery.
7. Large red wire at alternator with key on/ engine not running/ showed 23.6 volts.
8. I took the alternator off and had it tested at a reputable rebuilders shop. He said the alternator was ok as it put out consistent 14.2 volts at the post where the large red wire is hooked up.
9. I tried to check the ohms on the fusable link and may not have been doing this correctly but I got readings from 56 ohms to 94 ohms and the numbers steadily fell . I may not have done this test correctly. but I did verify 2 times I got no beep on my tester when I checked for continuity on the red wire from the end of the ring connector to the opposite ring end. No beep at all.
10. Engine running test- large red wire at alternator was showing 24.6 volts. Again the shop verified the alternator on their shop tester showed 14+ volts.
11. I had good connections at the solenoid, alternator, ground straps. No loose wires of nuts any where.


So I'm thinking the fuse link is blown. I had the loose nut on my breaker by the battery. The nut wasn't even finger tight. Not sure if it being so loose caused a spike in volts and blew the link. Your thoughts sir? Where should I go from here? Thanks again

[Savage]

Ohm test the fuse link...….easy

[EuropeanAM]

Either you were mistaken in your tests "key off" and "key on engine off" that resulted in 20+ volts, OR you have more than one battery tied together.

I suspect those readings were with the engine RUNNING... which would indicate a damaged Fusible Link Lead (reverse/cross polarity is what causes it).

As Savage suggested- perform an ohms test on that lead, if it's open circuit, order a new one and replace it.

[gaf11]

Could I take a piece of 10 guage wire make a fuse link to test and see if I m then getting the proper volts out of the alt. And then check battery voltage. If volts go to 24+ bang. I know the fuse link was bad and could order a new one.

[gaf11]

I meant if volts are at 14 volts from the alternator. Sorry.

[Savage]

Yes you could temporarily make a replacement link with a 100 amp circuit breaker, or fuse.

[gaf11]

Thanks for all the help. It was actually the fuse link. There is a 2 week time to get this part and $100 so I decided to make one myself. Used the 2 wires connecting the link...cut off the old link and used a 100 amp link from Autozone. Used new heavy duty ring connectors and brass rivets to connect the new link...shrink wrapped the assembly 2 times and , Sports fans we have a working alternator now! Thanks again for the help and good direction. Appreciate it again guys. Glynn

[EuropeanAM]

There is a 2 week time to get this part and $100

Not real keen on "making" these... but it sounds like you did a good job, considering.

If you need an OEM part in the future- check out Rhonda's post (pinned at the top of the Forum). This is something we usually keep in stock.