2004 4 stroke 75 hp wont charge battery

[turn2]

I have a 2004 merc 4 stroke carb motor . It is not charging the batt, i started the motor and checked voltage to the battery cables with them unhooked and the motor is only putting out 9 volts back to the battery.
I am thinking it is the rectifier. I do not have a manual for this motor so I am looking for either some advice on test procedures ,wire colors to check for output voltage from the rectifier. What is the rectifier output ? Could this be the stator . The engine runs fine.

Thanks for any advice
Danny

 

[turn2]

Re: 2004 4 stroke 75 hp wont charge battery

any opinions????
Thanks

 

[turn2]

Re: 2004 4 stroke 75 hp wont charge battery

Still needing help..Thanks

 

[Silvertip]

Re: 2004 4 stroke 75 hp wont charge battery

You NEVER EVER run an engine with the battery disconnected. I sincerely hope you did not fry the voltage regulator/rectifier. But since the damage may or may not be done, here is the right way to verify if the charging system is working.

1) Connect the battery.
2) Look at your instrument panel. Do you see a "voltmeter"? If not continue to step 3. If you have a voltmeter turn the key to RUN (not start) and continue to step 4.
3) Connect a voltmeter to the battery.
4) Note the voltmeter reading (should be 12.6 volts. Less if the battery is slightly discharged.
5) Start the engine and rev to about 1500 RPM.
6) Again note the voltage reading. If still 12.6 or less you have a bad charging system. If greater than 12.6 (should be 13.6 or so) the charging system is working.

 

[hanses]

Re: 2004 4 stroke 75 hp wont charge battery

The regulator is easy as pie to get to on the front of the motor just under the hood. 2 bolts and a quick disconnect -done. Not sure the price but the easiest thing to replace on the entire motor. Good luck

 

[turn2]

Re: 2004 4 stroke 75 hp wont charge battery

Thanks for the help. I do have a gauge on the dash. It reads low, I was just checking to see if the gauge was wrong with the volt meter. It is not charging according to the gauge and my meter.
It also looses charge over night . Battery is good.
I was lead to believe it could also be the stator.{reason for needing test procedures}.
Any thoughts on the stator killing the battery and not letting it charge?
I just dont want to buy a 4 or 5 hundred dollar part on a guess.
The engine runs like new. Just no charge.
Again thanks for the help.

Is the rectifier to only source connected with the battery charing?
No charge = bad rectifier ???

 

[j_martin]

Re: 2004 4 stroke 75 hp wont charge battery

I just dont want to buy a 4 or 5 hundred dollar part on a guess.

Get a manufacturer's maintenance manual and follow the procedures in it. The easiest way to limit parts expenditures is proper diagnostics.

You may have already ruined a good part with the wrong procedure. Odds are, though, that the original fault is the voltage regulator.

hope it helps
john

 

[hanses]

Re: 2004 4 stroke 75 hp wont charge battery

Holy crap -they want that much for that little part, or are you just guessing??

 

[sschefer]

Re: 2004 4 stroke 75 hp wont charge battery

If the 9vdc is correct and output from the stator is 18vdc as per some spec's then that could mean that one side of the bridge was out in the recitifer/regulator or the stator is bad.

The battery is the quazy unofficial regulator of voltage, a bad one could cause almost identical symptoms.

It's discharging overnight with the key off, (no accessories running except maybe the radio aux power). This could be be caused by a shorted regulator/recitifer but in my experience that usually results in no DC output at all, (fuze blows).

My vote is to have the battery tested.

 

[turn2]

Re: 2004 4 stroke 75 hp wont charge battery

I do not have a manual for this motor so I am looking for either some advice on test procedures ,wire colors to check for output voltage from the rectifier. What is the rectifier output ? Could this be the stator . The engine runs fine.

Thanks for any advice
Danny

I was hoping someone could tell me the wire colors and how much voltage my out put should be on those wires. Or maybe the ohms readings for the rectifier . I have all evinrude johnson manuals from 75 to present but no mercs. i dont do much mecr on my lake . So I was just asking.

 

[trendsetter240]

Re: 2004 4 stroke 75 hp wont charge battery

I was hoping someone could tell me the wire colors and how much voltage my out put should be on those wires. Or maybe the ohms readings for the rectifier . I have all evinrude johnson manuals from 75 to present but no mercs. i dont do much mecr on my lake . So I was just asking.

Silvertip already did, the voltage should increase to 13.6 or so on the battery when running at 1500rpm. The voltage regulator should put out 14.2v. The only thing that changes with engine speed is the amperage output.

If your battery is low or bad then the regulator may not be able to bring the voltage on the bat up.

I'd try putting that battery on a charger until it is fully charged then follow the steps Silvertip outlined.