inline 1500 charging problem

[robert2278]

on my 1975 merc 1500 runs perfect but the charging system appears to be having some issues ive checked the stator and rectifier and accordind to the manual im using they are passing the specs but they dont say what the stator should put out voltage wise has any body have any ideas on this

 

[wired]

Whats the problem? Keep in mind that stator charging system barely puts out enough current to keep the battery charged and even then it doesnt do that all that well. At anything under 2000 rpm you won't get over 12 volts from the stator if the battery is even a little discharged. Half hour at WOT you MIGHT get 14 volts. Theres a reason they didnt bother putting a voltage regulator in that system. It never gets to the point where it can overcharge.

 

[Big Red]

Just worked on one, when testing the stator you need a good meter. I tried 3 different meters and they all read different. Theirs only 2 wires that come off the stator that have anything to do with charging. They are connected to the rectifier. The rectifier changes the A/C power coming off the stator to D/C. The red wire coming off the rectifier goes to the main power block which comes off the battery.

Their is no kind of voltage regulator thats what confusses most people on the older O/B is the charging volts. Mine charges anywhere from 12.8 to 16 volts. I thought I had a problem seeing 15 to 16 volts and asked several people and got nothing but BS answers why I was getting over 14.5 volts.

Any alternator system charges between 13.5 to 14.5 but the older O/B's will go to 16. What keeps from cooking the battery is the older O/Bs puts out very little amps. I thinking the amps are around 8-10 unlike a alternator that goes from 30 to 100.

Change the rectifier its the cheapest part, if that does not fix it its the stator. Make sure the red wire is good going to that main block. Follow the wire you will know what I am talking about.

 

[DropTop5.0]

I don't know crap but I'm trying to read and learn. What BR said is what I thought to be true. And I heard its important for for an inline guy to have a volt meter, that way you know if your in the 16 volt range. And if you are, turn your lights on or turn the stereo on to nock the voltage down in order to save your battery from cooking.

 

[Big Red]

I don't know crap but I'm trying to read and learn. What BR said is what I thought to be true. And I heard its important for for an inline guy to have a volt meter, that way you know if your in the 16 volt range. And if you are, turn your lights on or turn the stereo on to nock the voltage down in order to save your battery from cooking.

Thats not true it will not cook your battery when charging at 16 volts. The reason why is the amp out put is very low on the older O/B.

 

[wizard8575]

I had a bad rectifier on my 1400 and my tach was not working either. Do you have one? I tested mine on the bench with a meter and it was very obvious it was dead. I don't remember the procedure but it was fairly simple. When I get home I will look it up.

 

[robert2278]

the boat is set up with a tach but its not hooked up im wondering if mabey half the stator is bad because the engine seems to run ok it is putting out a/c voltage but the manual im using does not specify how much should be there is there any way u could fire up yours and see what yours is putting out then i could make repairs to mine also the internal wiring is in pretty bad shape so im getting that repaired hopefully by the weekend

 

[Big Red]

See the two wires coming off the stator going to the rectifier. Check the red wire coming off the rectifier to see how many volts are their. Mite need to bring the rpms up. The tach wire also comes off the rectifire.

You can run a wire direct to the battery off the pos. side of the rectifire if needed.

8 out of ten times the rectifire is the problem. My case I had a bad rectifire and stator