replaced rectifier and it still is not charging.

[Pokertrampp]

1988 johnson 120hp, motor was not charging, tach was not working, all test results indicated rectifier needed replacing. I replaced rectifier and it is still not charging. and tach is still not working

 

[wilde1j]

Re: replaced rectifier and it still is not charging.

Did you test stator for presence of AC voltage to R/R?

 

[Pokertrampp]

Re: replaced rectifier and it still is not charging.

Did you test stator for presence of AC voltage to R/R?

no, not sure how to. I checked the ohms and it checked out ok, but I did not see anything saying to check ac voltage. how do I check that, and if that is the problem could it cause a mis at all rpm ranges but gets signifiganly worse as rpms are increased. I checked the voltage between the brown and brown with yellow stripe wires and it reads 296v and only increases or decreases about 1 or 2 tenths of a volt with rpm increase

 

[wilde1j]

Re: replaced rectifier and it still is not charging.

Check AC across yellows to R/R. Should get >25VAC. If not there, suspect wiring or stator NG.

 

[Pokertrampp]

Re: replaced rectifier and it still is not charging.

???

 

[Pokertrampp]

Re: replaced rectifier and it still is not charging.

Check AC across yellows to R/R. Should get >25VAC. If not there, suspect wiring or stator NG.

do you mean check between the yellow and yellow/gray wires? ,if yes then I have aprox. 19-20vac at idle but it increases as rpms increase, I only increasedrpms a little and it went up to 28vac.

 

[Pokertrampp]

Re: replaced rectifier and it still is not charging.

???

 

[Joe Reeves]

Re: replaced rectifier and it still is not charging.

The fact that the tachometer functions when connected to the yellow lead of the stator proves that the alternator is functional as the tachometer operates off of the alternator's 6 pulse system.

To check the stator with a ohm meter, disconnect the yellow leads.......

On high ohms... connect the meter leads between those two yellow leads. The reading should be infinite.... looks like a dead short.

Still on high ohms... connect one meter lead to a yellow wire, the other meter lead to ground. There should be absolutely no reading. Connect the meter lead to the other yellow wire. There should be no reading there either.

Meter on low ohms... Again connect meter leads between the two yellow leads. The ohm reading should be very low... not over 1.0 ohm.

What readings do you find if different?

The rectifier.... I assume this is the water cooled voltage regulator/rectifier assembly type unit? If so, are you sure you have it wired correctly as per the wiring diagram in your service manual? Positive (+) voltage being applied to the RED wire of the unit?

 

[Pokertrampp]

Re: replaced rectifier and it still is not charging.

The fact that the tachometer functions when connected to the yellow lead of the stator proves that the alternator is functional as the tachometer operates off of the alternator's 6 pulse system.

To check the stator with a ohm meter, disconnect the yellow leads.......

On high ohms... connect the meter leads between those two yellow leads. The reading should be infinite.... looks like a dead short.

Still on high ohms... connect one meter lead to a yellow wire, the other meter lead to ground. There should be absolutely no reading. Connect the meter lead to the other yellow wire. There should be no reading there either.

Meter on low ohms... Again connect meter leads between the two yellow leads. The ohm reading should be very low... not over 1.0 ohm.

What readings do you find if different?

The rectifier.... I assume this is the water cooled voltage regulator/rectifier assembly type unit? If so, are you sure you have it wired correctly as per the wiring diagram in your service manual? Positive (+) voltage being applied to the RED wire of the unit?

The Tach is not working, not when its wired correctly or when its wired with the yellow and gray together, I do not know yet if the tach itself is faulty I just recently purchased the boat and have been doing some work to it and just revcentlystarted to work on the motor itself, the tach has not worked since I have owned it. I took a shot and guessed that since the tach was not working and the system is not charging and all connections are clean the rectifier/regulator must be bad. I will say that the motor has a noticable mis during idle and gets signifiganly worse as rpms are increased and anything over 1500rpm it will occasionaly cut out like I turned the key off and back on. I am certain there is some type of ignition problem just not sure yet if its in the stator, timer base or power pack. the stator checked out ok but I keep getting conflicting answers about how to test the stator and power pack so they have not been checked other than the previously mentioned results. I will try to do the test you mentioned asap, but I may not get to it until the weekend. Thanks again for the help.

 

[Pokertrampp]

Re: replaced rectifier and it still is not charging.

The fact that the tachometer functions when connected to the yellow lead of the stator proves that the alternator is functional as the tachometer operates off of the alternator's 6 pulse system.

To check the stator with a ohm meter, disconnect the yellow leads.......

On high ohms... connect the meter leads between those two yellow leads. The reading should be infinite.... looks like a dead short.

Still on high ohms... connect one meter lead to a yellow wire, the other meter lead to ground. There should be absolutely no reading. Connect the meter lead to the other yellow wire. There should be no reading there either.

Meter on low ohms... Again connect meter leads between the two yellow leads. The ohm reading should be very low... not over 1.0 ohm.

What readings do you find if different?

The rectifier.... I assume this is the water cooled voltage regulator/rectifier assembly type unit? If so, are you sure you have it wired correctly as per the wiring diagram in your service manual? Positive (+) voltage being applied to the RED wire of the unit?

my results were:

On high ohms... connect the meter leads between those two yellow leads:
0.00

connect one meter lead to a yellow wire, the other meter lead to ground.:
0.00

Meter on low ohms... Again connect meter leads between the two yellow leads. The ohm reading should be very low... not over 1.0 ohm.:
02.6

I assume the last reading is a "bad" readin and indicates a problem, does this mean the stator is bad, is this the reason the charging system is not working, and could this be the cause of the "mis" when the motor is running.

as far as if I wired it correctly, I wired it accoding to the manual, but there is an issue with the 2 yellow wires, the manual calls for a yellow wire and a yellow/gray wire..neither yellow wire has any gray on it so I am not sure if those two wires are in the right or wrong places. I was gonna switch them, but I know the rectifier is sensitive so I put it back on the way it came off. keep in mind it was not charging when I purchased the boat and I do not know if the P/O wired it correctly. also there was a third purple wire not mention an any schematics I looked at (it goes to VRO which is disconnected) I left the purple wire off.

 

[Pokertrampp]

Re: replaced rectifier and it still is not charging.

???

 

[daselbee]

Re: replaced rectifier and it still is not charging.

That second reading...where one meter lead is grounded....and you get zero ohms to the yellows...that indicates the stator windings are grounded. Bad stator.
Also, for more verification, put the meter on AC volts scale, range maybe 20 or so...(depends on your meter), start engine and measure volyage across the two yellows.
With it shorted as your measuremnets indicate, you should be showing zero volts.

A good stator will show 20-25 volts AC when engine is idling. (no need for a DVA on this measurement).

 

[Pokertrampp]

Re: replaced rectifier and it still is not charging.

A good stator will show 20-25 volts AC when engine is idling. (no need for a DVA on this measurement).

it shows 18VAC

 

[Vic.S]

Re: replaced rectifier and it still is not charging.

connect one meter lead to a yellow wire, the other meter lead to ground.:
0.00

That's the problem. I guess a short from the stator coil to ground. You did have the stator wires disconnected when you tested? and the other was not accidentally grounding!

Double check before you rip the stator out and throw more money at it.

Both stator wires to ground should show infinite resistance.

Dont worry about having two yellows instead of a yellow and a yellow/gray. They can go either way!

 

[Pokertrampp]

Re: replaced rectifier and it still is not charging.

That's the problem. I guess a short from the stator coil to ground. You did have the stator wires disconnected when you tested? and the other was not accidentally grounding!

Double check before you rip the stator out and throw more money at it.

Both stator wires to ground should show infinite resistance.

No, I guess I misunderstood. I did not disconnect the stator, I just disconnected the 2 yellow wires like mentioned in the previous post suggested. I will retest tonight and post results.

 

[daselbee]

Re: replaced rectifier and it still is not charging.

We are only talking about the yellows here. Should be open to ground, and a low resistance between them.
When running, and yellows disconnected, should read 20 - 25 vac. Even 18 sounds good, IF you have measured correctly. Maybe some meter lessons...

 

[Vic.S]

Re: replaced rectifier and it still is not charging.

Just to clarify.

disconnect the two stator wires ( yellow and yellow gray) measure the resistance between them and ground ( either one or both if you like) There mst be infinite resistance.
If you get a reading then there is a short to ground.

Recheck the resistance between them. ( while still disconnected)
Should be low. Joe says less than 1 ohm but it is difficult to read these very low resistances accurately sometimes.

 

[daselbee]

Re: replaced rectifier and it still is not charging.

Just to clarify.

disconnect the two stator wires ( yellow and yellow gray) measure the resistance between them and ground ( either one or both if you like) There mst be infinite resistance.
If you get a reading then there is a short to ground.

Recheck the resistance between them. ( while still disconnected)
Should be low. Joe says less than 1 ohm but it is difficult to read these very low resistances accurately sometimes.

Exactly. Well clarified. Especially the point about reading low resistances.

 

[Pokertrampp]

Re: replaced rectifier and it still is not charging.

Just to clarify.

disconnect the two stator wires ( yellow and yellow gray) measure the resistance between them and ground ( either one or both if you like) There mst be infinite resistance.
If you get a reading then there is a short to ground.

Recheck the resistance between them. ( while still disconnected)
Should be low. Joe says less than 1 ohm but it is difficult to read these very low resistances accurately sometimes.

That is exactly how I did it, but I did not have them disconnected when I did the running test and got a reading of 18VAC. and the test that Joe says should be <1.0 I showed 02.6.

 

[Barnacle_Bill]

Re: replaced rectifier and it still is not charging.

That 02.6 reading is good enough. Reading low ohms accurately requires a good meter that you can compensate for the resistance in the leads. No where in this thread have I seen where you actually checked the output to the battery. Have you done this? Measure the voltage at the battery with the motor off, then start the motor and check it again. As RPMs increase you should see an increase in voltage.