How To Diagnose A Generator That Has No Power Output.

Below is a video of how to test a generac exl8000 generator to see why there is no power output.

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Here we have an EXL8000 generac generator. The owner went to hook it up after losing power during hurricane sandy and discovered that it runs fine but it has no power output. So we will be showing you how to test if it is the automatic voltage regulator also known as the AVR most likely the cause or if it’s the part that generates the electricity.

Next grab a 1/4-Inch ratchet, small 1/4-Inch extension and a 7mm socket with that remove the four 7mm bolts that hold the cover in place. Next wiggle the gourmet out of the cover so you can completely remove the cover.

At the top you will see your automatic voltage regulator also know as an A.V.R. That is what we will be testing. You also might see a black tube looking thing that is an inline booster the order generators will have it the newer ones they discontinued using it.

It might be a good idea to take a picture with a digital camera before disconnecting wires so in case you don’t remember where they go you have something to use as a reference. Next remove the two leads from the left side of the A.V.R bend them out so you can easily test them later.

Next we will remove the positive (red) and negative (black) leads off the bush set coming from the AVR. Keep in mind that the one closer to the bearing is the positive (red). Next you will want to use electrical tape and tape both leads separately so they can’t touch each other or the housing.

Next you will need a 12Volt DC power supply. You can use a car battery or a compact drill battery. You will also need two insulated alligator test leads. It’s a good idea to have two different color leads.

Next let’s hook up the two alligator clip leads to the brush set. The one near the shaft/ bearing is the positive (red one). The one in the back in the negative (black one). Next clip the other end of the positive (red one) lead to the positive of the 12volt DC power source. DO NOT hook up the negative at this time.

Next start the generator in a well vented area. Let the engine speed stabilize for 5-6 seconds and at that point connect the other end of the alligator clip to the negative of the 12 volt DC battery.

While its running and your negative lead hooked up take your electrical tester and set it to VAC and test the two exciter winding wires that we removed off the left side of the A.V.R. You should have a minimum of 60 volts. If you have around 60 volts that means your automatic voltage regulator or also known as AVR needs replacing. Part #20585GS. If you don’t have around 60 volts that’s mean the part that generates the electricity is bad. You might want to take it in for service or think about buying a new generator.

If the generator has been stored for a while you might have lost the Residual Magnetism. The testing method is also the way to restore the resista magnetism. So if your generator was stored for a while you might want to reconnect all the wires and retest for power output it might save you from having to buy and replace the AVR. It is recommended that you start and load a generator at least every 3 months to ensure the brushes stay clean and that it doesn’t loose it’s Residual Magnetism and be sure to use some fuel treatment to keep the gas from going bad.







Thanks for the info. I have to check my Briggs & Stratton 5500 watt generator. I can start the engine with the breaker set on 220. But will not produce any power. And if I start the generator with the breaker on 110 and try to set it on 220. It will kick it back to 110. Either way, there is no power. If you have any suggestions please let me know your thoughts. I purchased the generator in 2008.It is a Storm Responder; Thanks Thomas!

Hello, Your welcome hopefully it helps. If the generator has been stored for awhile and not used it might have lost it’s resista magnetism. The video above is also the way to restore the resista magnetism. So you might want to test it/ restore the resista magnetism like in the video and then hook all the wires back up and try it and see if there is power output. Might save you from having to buy the AVR. A generator should be started and loaded at least every 3 months to ensure proper operation by keeping the brushes clean and to make sure it doesn’t loose the resista magnetism. I have heard both good and bad stories about the storm responder generators. Change/Check the oil regularly as i am pretty sure they don’t have the low engine oil shut off and keep it level when it’s running. Good Luck.

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However, if generator starts and runs fine, but not showing a voltage, and has been sitting a while, let it run for about 10 minutes, turn off and start again.

Voltage may show on second attempt, as my Duromax 10, 000 did.

Just thought I would pass on.

It could have lost its residual magnetism. So you can plug a drill with a cord into one of the 110 volt plugs then squeeze the trigger/ power button and turn the drill chuck by hand 4-5 times to restore the residual magnetism. You could also have a bad AVR which is not stepping up the power.

OK, thanks for the video but could you clarify something for me?

“You should have a minimum of 60 volts. If you have around 60 volts that means your automatic voltage regulator or also known as AVR needs replacing.”

So if it has a “minimum of 60 volts” the AVR is OK, but if it has “around 60” volts it needs replacing?

The AVR should be putting 24 volts DC into the brush set which is going to multiply the input by about 5. So normally it would be getting 24 volts supplied to the brushes. So 24v x 5 would give you 120 volts coming out. So if you put in 12 volts into the brush set.. 12v x 5 you should get 60 volts coming out on the test meter. So if the generator can’t put out the 120 volts to the plugs and you take it apart and run this test and you get pretty close to the 60 volts plus or minus a few then the voltage regulator is bad and not supplying the 24 volts it needs to. As we took that out of the equation. If you run this test and you have no output or really low you may want to look at the brush set, connections, or if the generator has lost it residual magnetism.

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