No tach,no charging

[Ifishmuskie2]

With engine turned off I get battery voltage at the two yellow wires from the stator at the junction box near the coils.

 

[boscoe99]

It went from working great to no charge and no tach.
That’s why I changed the rectifier.
Maybe the new rectifier is ng also.
How do I check it?
I’m going to check everything i can see.

It is a voltage regulator. Not just a rectifier.

 

[boscoe99]

With engine turned off I get battery voltage at the two yellow wires from the stator at the junction box near the coils.

You are seeing battery voltage on the stator output wires with those wires not connected to the regulator?

 

[boscoe99]

There is no bench test for a voltage regulator that I know of. You could feed it 16VAC and see what it puts out. It should try to put out about 14VDC

Let's see, your furnace thermostat runs on 16VAC, so cannibalize your heating system and go from there.

This is from a Mercury service manual for the OP's voltage regulator.

But even if the regulator tests well, with no DC output with sufficient AC input, the regulator is faulty.

 

[boscoe99]

Yellow wires from the alt are before the reg/rect , but if one had the meter set to dc while testing an ac output the meter would show a reading and depending on the dampening function on a particular meter you may see a reasonably stable reading ....however wrong it was .
My Fluke 179 had a reading dampener that can be disabled .

Correct.

Just connected my meter to a 120 volt AC outlet. Set on DC. A steady 0.24 DC volts were seen.

 

[Ifishmuskie2]

I just ran the engine with the two yellow wires coming from the stator disconnected.
I get 18v when I touch both wires with the probes.
So stator is good?

 

[Ifishmuskie2]

My old regulator tests as open circuit on all but one yellow wire test.
I have to break for lunch.

 

[boscoe99]

I just ran the engine with the two yellow wires coming from the stator disconnected.
I get 18v when I touch both wires with the probes.
So stator is good?

Yes.

Now connect the yellow input wires to the regulator with the red output wires connected to the battery and the regulator case grounded. You should see ~ 14 DC volts (meter set on DC) at a fast idle.

Important that the regulator is connected to the battery. Otherwise no DC output.

 

[Ifishmuskie2]

I did that and not working.
I just checked every wire in the circuits by ohms on the connection. All of the connections are good.
I think the new regulator is no good.
I’m ordering another one?

 

[99yam40]

I just ran the engine with the two yellow wires coming from the stator disconnected.
I get 18v when I touch both wires with the probes.
So stator is good?

was that 18VAC?

 

[Mc Tool]

yes, but OP said no AC voltage on the yellow wires, when the engine was running, but DC voltage there? That is not the way it should work.

If there really was DC voltage on the yellow wires, the stator would be an electromagnet and discharge the battery.

no he didnt , he said he had the meter set to dc whilst testing an ac output , easy mistake , and with a faulty stator who know what the meter could say .......might have been mv , another easy mistake on an auto ranging meter

 

[99yam40]

no he didnt , he said he had the meter set to dc whilst testing an ac output , easy mistake , and with a faulty stator who know what the meter could say .......might have been mv , another easy mistake on an auto ranging meter

well he wrote this also, but have no idea what the meter was set to.
AC or DC

"I just ran the engine with the two yellow wires coming from the stator disconnected.
I get 18v when I touch both wires with the probes."

 

[Ifishmuskie2]

Yes 18v ac.
With a probe on each yellow wire coming from stator.
With engine running and two yellow wire disconnected from engine.
So stator is ok?
I guess the new regulator is no good.
I can’t see anything else.

 

[boscoe99]

I did that and not working.
I just checked every wire in the circuits by ohms on the connection. All of the connections are good.
I think the new regulator is no good.
I’m ordering another one?

So on the red and black wires you are seeing battery voltage only when the motor is off but then no increase in voltage when the motor is running at a fast idle?

 

[Ifishmuskie2]

Yes that is correct.

 

[Mc Tool]

you should be getting 50+vac out of the stator at high revs and a bit below 20vac at idle .... Id say your stator is puckerood . This event , fried reg/rect , is often accompanied with a burnt out stator . Usually the reg shorts out and that causes high current flow in the stator and burns that out too . regs and stator can fail individually but when the reg is actually burnt ( as opposed to just not working ) it usually takes the stator with it . I would now remove the flywheel and have a visual on the stator .... some coils ( not all of them are alt coils ) may look discolored or even burnt .

 

[Ifishmuskie2]

The engine has a warning.
When cowl off no more then 3000rpm.
So I only had it at about 800 rpm when I checked the yellow wires from the stator.
Ok so next step is remove stator for inspection?

 

[Mc Tool]

The engine has a warning.
When cowl off no more then 3000rpm.
So I only had it at about 800 rpm when I checked the yellow wires from the stator.
Ok so next step is remove stator for inspection?

yeah , the stator is under the flywheel so you would have to remove that ... and that can be a mission , even getting the nut undone aint easy . You really need a proper puller suitable for the job , and some proper way of holding the flywheel so you can undo the nut .
If you dont have a knowledgeable friend to help I would suggest a you tube video ( there are a few ) for help , but make sure the motor in the vid looks like yours . You can search for a 115hp Mercury motor too as the Mariner is made by them .

 

[Dukedog]

jus curious as ta why you don't have an oem manual for this motor???.. doin' things your self would make your life a bunch easier..... jmo.

 

[Ifishmuskie2]

I never needed a manual until now.
Where can I get one?