Question about Generac Electrical Supplies

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I have Generac GP8000E (G0069310) and the engine runs great but generates only 2-3 volts.

This is a BRUSHED EXCITATION generator with a voltage regulator. When I received the generator the voltage regulator was missing, so I replaced it. I get 2-3 volts when using a meter directly connected to the voltage regulator or alternator. The fuses on both the GFCI outlets will not reset. The 208-volt outlet has 2-3 volts. Do I need to flash the generator? If so how do you flash a brushed generator? Thanks.

Posted by Matt Johnson on

  • Matt Johnson
    Matt Johnson Aug 19, 2019

    I already replaced the AVR. No change. Thanks for the advice though.



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Most of the time it is the AVR that has blown. Check out our videos on how to test them.
We hold your AVR in stock and have a whole Help Center dedicated to helping people fix their Portable Generators. Check it out on our site.

Parts Spares for Generators and Small Engine Machinery
I have Generac GP8000E (G0069310) and the engine r - image-2fwsrbehqcya13uxwt41l5dc-1-0_8.jpg

Posted on Aug 19, 2019


5 Related Answers


  • 3 Answers

SOURCE: portable generator low voltage

85 volts represents residual voltage. It is possible that your unit sat for an extended period and lost it's magnetism or the excitation system failed under load. check your manual for a procedure to "flash the field". If that is not successful, e-mail me and I'll tell you how to trouble shoot the failure.

Posted on Jan 04, 2009



  • 4 Answers

SOURCE: Low voltage output from inverter

I am thinking this a high impediance device problem and this is normal operation - the user manual of my inverter warns about use with high impediance devices - if not I am interested also...

Posted on Mar 03, 2009

Phil Rivera

  • 83 Answers

SOURCE: mitsubishi mgb 4000 wiring diagram

Here is a manual for a newer mge model. I don't think your going to find a manual on the older mgb around and they tend to be very similar from one model to another so it should help. Though you should be able to get parts.

As for the gfci brand, I have not had any problems with any of the brands out there. So the cheapest is the best. The 30amp socket could be 110 or 220vac. If there is a selector switch on your machine. If not, there should be a NEMA number on the face of the socket (ie 15-5R). The R stands for receptical while a P stands for plug.

Here is a plug configuratio diagram that will help identify your plug and the voltage it puts out. These are standard so you can be sure that if it the same plug it will put out the same power. Be carefull to ensure which side is larger or has a tab is correct.

While replacing the plug just swap wire for wire in the same place as your new plug. Gold connector to gold and silver to silver.

The inside of a small generator is very similar and if this don't help I can walk you through any connections you have questions on. Pictures would help if it comes to this.

Posted on Apr 02, 2009


  • 867 Answers

SOURCE: buffalo tools 4,000 watt generator

wow, that is high, i would think voltage regulator is faulty also

Posted on Aug 17, 2009


Craig Butler

  • 1730 Answers


When you flash the field, are you going + 12 volts to the top or right side brush? Negative to the other brush? Try three times for 2 seconds?

If you need further help, I’m available over the phone at

Posted on Sep 26, 2009

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When the generator set speed reaches the rated speed, the AC exciter stator excitation circuit switch is closed and the voltage regulator is adjusted to the maximum value when the generator speed reaches the rated speed.

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Alt has a small red wire in the plug. what is it for

The circuit it forms part of runs from the battery, throug hthe charge warning light on the dash, the the voltage regulator on the alternator. The wire does two jobs.

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NO. the capacitor resonates with a winding it is in parallel with as part of the voltage regulation.

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I can't tell you what type of rotor excitation you have without the model number but,

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My generator starts and runs great, It is not

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  3. Use an analog multitester to check the continuity of the carbon brush and the field coil.

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The armature (rotating field) is powered by the voltage regulator for 'excitation' which is the term describing a magnetic, revolving field. This magnetic field 'induces' voltage into the stator windings (stationary outer winding), producing voltage for use at the recepticles. Some older generators used a 'permanent magnet field, instead of using a powered winding from a regulator and the voltage and frequency were set by the RPM.
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If you need further help, I’m available over the phone at

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