Anoyone know how to test a stator?

[bayprowler]

I am trying to test the stator on my 1987 140hp Johnson. The manual says to check resistance using an ohmeter on the two yellow leads coming from stator. I tried that and don't show any reading at all. Am I doing the test correctly?

 

[wifisher]

Re: Anoyone know how to test a stator?

No reading is an open cirsuit, which means a bad stator. Put the two leads together and be sure that you get a reading near zero ohms. This will tell you the meter is working. If you get no reading with the leads together, fix the meter. Then just like you said. One lead on each wire. doesn't matter which. The manual should give you an acceptable range. If outside of that range, the stator is bad.

Also make sure the wires are disconnected while doing this test.

 

[guitman32]

Re: Anoyone know how to test a stator?

To properly test the stator you will need a peak reading multimeter, or an adapter that works with your existing multimeter. Sear for DVA meter and you'll find out how to make your own.

Not sure of the specific values for your motor, but there are two tests you can perform on your stator: resistance test and output test. You will need the DVA for the output tests only.

Also there are sites that I do not have offhand that outline the test procedures and expected voltages for the various components. Again, searching will help you there.

 

[bayprowler]

Re: Anoyone know how to test a stator?

Thanks guys. I checked the meter - when I put the 2 leads together I got a reading of 0 ohms. It looks as if I have a bad stator. But I will search for a DVA meter as well just to make sure. These multimeters are more complex than I thought.

 

[boobie]

Re: Anoyone know how to test a stator?

Are you testing for a no spark condition or a battery charging prob??

 

[bayprowler]

Re: Anoyone know how to test a stator?

A batt charge problem. I already installed a new regulator/rectifier but that didn't solve the problem. I tested the regulator for output Amps - none. The tach is not reading as well. The gray wire that's supposed to send tach pulse does not read any volts at all.

 

[boobie]

Re: Anoyone know how to test a stator?

There are no output tests for the charging side of the stator ( two yellow wires ). The only test is with an ohmmeter and if your ohmmeter is good and you show an open circuit, your stator is bad. If you're close to a Radio Shack go buy a 10 ohm,10 watt resistor and check your ohmmeter with that. I keep one just to check my ohmmeters if I have any question about them.

 

[bayprowler]

Re: Anoyone know how to test a stator?

thanks for the advice, boobie, I will get the resistor and check my ohmeter. the output that i tested was for the regulator...i tested the output Amps according to the manual - attaching the multimeter in series (as a 10A ammeter) between the red power lead from the regulator and the battery side of the starter solenoid. Is that right?

 

[seahorse5]

Re: Anoyone know how to test a stator?

A 10 ohm resistor will only tell you if the meter is accurate at 10 ohms, plus or minus the tolerance.

To test a stator, you need a meter that is accurate to 1/100 of that resistor and many are not.

Many high output stator leads only have a 0.1 to 0.5 ohms of resistance and others may be around 1 ohm. You need a meter that can read those low resistances correctly.

 

[boobie]

Re: Anoyone know how to test a stator?

You are correct on the test you did. Did you get any reading with the ampmeter ?