charging system problem

[cbeam2]

1990 John 150

It seems to be one thing after another on this motor. I just built the carbs and it seems to run great. I just happened to look at the volt meter on the dash while I was running it and noticed it only showed 12v. I know before it showed 14 or so.

I checked it at the battery with volt meter but it's just not charging. The book says to hook an amp meter up inline but I don't have that type amp guage. Is there another method I could test it with?

Chuck

 

[Barnacle_Bill]

Re: charging system problem

If your volt meters are not showing an increase in voltage while running there is no need to test any other way. Test your rectifier/regulator according to your manual. While you have it disconnected check the 2 yellow leads that come from the stator to the rectifier.

 

[F_R]

Re: charging system problem

Also, be sure to inspect your battery connections. Loose or corroded connections are the #1 cause of rectifier problems.

 

[cbeam2]

Re: charging system problem

New battery and everything I can see looks good. I am going to double check connections tomorrow but I doubt that anything came unplugged around the motor.


Chuck

 

[HighTrim]

Re: charging system problem

Not unplugged, but a bit corroded or a nick in the wiring can cause problems. Go over your connections with a file then tighten them back down, dont just eye them up and figure they are ok. Look for buldges in the wiring, or any nicks, tears abrasions, etc... Then test as per your manual. Good luck.

 

[cbeam2]

Re: charging system problem

I assume if something has gone out it would be the stator. Am I correct or would rectifier also cause this?

The service manual says to test the stator with an inline amp meter. I do not have one so is there an alternative method?

Chuck

Oh, and the tach doesn't work either if that's an indication of a related problem.

 

[HighTrim]

Re: charging system problem

If your tach is shot, your rectifier is shot. That is where the tach gets its info from. Did you, by any chance hook ur battery up backwards, even for a second, lately? That could fry a rectifier real quick. Or loose or dirty connections as FR stated. Re test the rectifier, just to be sure before buying a new part, then figure out why it went.

Disconnect all 3 wires. There is a diode between each yellow wire and red wire, and a diode between each yellow wire and ground. That makes 4 diodes in total.

To test your rectifier place your ohmmeter in HI OHMS scale.

1. Connect your ohmmeter between one yellow wire and red wire. You will have either a high or low resistance. Reverse leads, and note reading. Infinite or very high reading in both checks indicates diode open. Zero reading in both checks indicates diode is shorted. Normal diode will show a reading in one direction and no reading in other

2. Repeat with the other yellow and red.

3. Repeat with one yellow and ground

4. Repeat with the other yellow and ground.

If it passes all 8 tests the rectifier is good. Otherwise it is toast.

Also, while you are at it, do a resistance test across the two yellow wires from the stator that were connected to the rectifier. Should be a low resistance continuity. Then check from one of those wires to ground. Should be no continuity to ground.

 

[cbeam2]

Re: charging system problem

It sounds like I must have been wrong by saying I had seen the dash volt meter higher than 12v. I say this now because the tach has not worked since I purchased the boat. This boat had been sitting up for several years prior to me purchasing it.

I will test recifier.


chuck

 

[HighTrim]

Re: charging system problem

After that test the stator. Disconnect the yellow lead and yellow /gray lead at the terminal block. Connect the red meter lead to either yellow lead and meter black lead to ground to check for shorts. An infinite reading on HI ohms scale indicates the windings are good. Connect the ohmmeter on LO ohms scale between the yellow and yellow/gray. A reading of .25 ohms + or - .1 indicates the windings are good, and an infinite reading indicates the windings are open. If windings are found to have failed, the stator must be replaced.

 

[cbeam2]

Re: charging system problem

If your tach is shot, your rectifier is shot. That is where the tach gets its info from. Did you, by any chance hook ur battery up backwards, even for a second, lately? That could fry a rectifier real quick. Or loose or dirty connections as FR stated. Re test the rectifier, just to be sure before buying a new part, then figure out why it went.

Disconnect all 3 wires. There is a diode between each yellow wire and red wire, and a diode between each yellow wire and ground. That makes 4 diodes in total.

To test your rectifier place your ohmmeter in HI OHMS scale.

1. Connect your ohmmeter between one yellow wire and red wire. You will have either a high or low resistance. Reverse leads, and note reading.
Reading on Yellow-3676 Reading on Yellow w/stripe-3700
Infinite or very high reading in both checks indicates diode open. Zero reading in both checks indicates diode is shorted. Normal diode will show a reading in one direction and no reading in other

2. Repeat with the other yellow and red.

3. Repeat with one yellow and ground No ground to either yellow wire
4. Repeat with the other yellow and ground.

If it passes all 8 tests the rectifier is good. Otherwise it is toast.

Also, while you are at it, do a resistance test across the two yellow wires from the stator that were connected to the rectifier. Should be a low resistance continuity. Then check from one of those wires to ground. Should be no continuity to ground.

On the stator wires... No short to ground on either wire but my meter shows "000" between the two yellow wires. I'm a little ignorant on ohms here but the book for my amp guage says that anything under 400 ohm reading will show as continuity. Do I really need an analog meter for these tests?

 

[HighTrim]

Re: charging system problem

"Reading on Yellow-3676 Reading on Yellow w/stripe-3700"

What happened when you reversed the leads for the meter for these two?

Your multimeter will work for this. Remember if it even fails one of the tests, it is no good and needs to be replaced.

 

[cbeam2]

Re: charging system problem

"Reading on Yellow-3676 Reading on Yellow w/stripe-3700"

What happened when you reversed the leads for the meter for these two?
It read 0 when I switched the leads around.Your multimeter will work for this. Remember if it even fails one of the tests, it is no good and needs to be replaced.

If I interpret the readings correctly then both rectifier and stator are bad. Would you come to the same conclusion?

Back to your previous question of connecting the battery wrong..No I did not but the battery that was in the boat when I purchased it may have had a short in it because it never would charge up.

Chuck

 

[HighTrim]

Re: charging system problem

Ok that is what it is suppose to read. A reading in one direction (which you had, 3700) and 0 when reversed (which you had)

Was this the scenario for all the tests for the rectifier? Or did any of the tests fail?

 

[cbeam2]

Re: charging system problem

Now I'm confused (ok I am already confused but it's worse)??? That is the rectifier test results.

Y to red is 0 one way and 3676 switched
y w/stripe to red is 0 one way and 3700 the other
Neither yellow wire from rectifier has a short to ground.

Evidently my digital meter will not do a low range so I borrowed an analog meter from a neighbor and retested stator.

No short on either wire from terminal block.
35 ohm reading across yellow and yellow/gray


Chuck

 

[cbeam2]

Re: charging system problem

Well duh, I guess the stator is bad. His meter didn't work right so I assume my meter was correct and it is indeed bad.

thanks for your help

Chuck

 

[cbeam2]

Re: charging system problem

OEM stator or is aftermarket one ok? Who has good prices.


Chuck

 

[ezeke]

Re: charging system problem

Is that a regulated, water cooled rectifier? If so, you can't test it as described above, but you can isolate some problems by following Joe Reeves' tach test:

http://forums.iboats.com/showthread.php?t=190636

 

[cbeam2]

Re: charging system problem

I have no idea if it is or not. How do you tell?

The stator is testing bad though by the above method of testing. There is no resistance measured between the yellow wires.

Chuck

 

[ezeke]

Re: charging system problem

Describe the rectifier and the wires leading from it. Most newer unregulated rectifiers have 3 wires, older ones have 4.

The regulated rectifiers are mounted between the cylinder banks so that their base is cooled by circulating cooling water. They generally have 5 or more wires.

On any rectifier, connect a good voltmeter directly to the battery with the engine off and take a reading. Then start the engine and take a reading.

 

[cbeam2]

Re: charging system problem

It has 5 wires and is located about half way under the fly wheel in the center of the block.

Chuck