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Hank F.
Hank F., RV tech - emphasis on gensets
Category: RV
Satisfied Customers: 15188
Experience:  RV tech since the beginning of the millenium.
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While replacing a fuel pump on my Generac 65K RV generator,

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While replacing a fuel pump on my Generac 65K RV generator, I accidentally caused a ground short which blew the fuse for the generator. I replaced the fuse and installed the fuel pump and the generator started fine, but I have no power coming out to my RV. The two breakers seem to be working right and I have also tried keeping the start switch depressed to stimulate the magnetic field of the stator but still no power. I have penned the junction box to find a voltage regulator with 6 leads and encased in a plastic type black casing and an adjustment screw and with a red LED which does not light up. Also found two relay type switches and another encased plastic with 6 leads coming off of it. I am trying to figure out what I need to replace or repair to get this working right. Any ideas?
Customer: replied 11 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 11 months ago.
Still awaiting a response

Hello, my name is ***** ***** I am going to assist you with this.

What are the model and serial numbers of the genset?

Customer: replied 11 months ago.
Hank, i just got your message and am in bed (rough day). Can i call you tomorrow with the info you need?

I work 2 jobs, and help on Just Answer in the evenings.

I can not be online 24/7, but am online almost every day.

I do not have to be online for you to reply. If you post your reply, I will get it when I log on.

But I can do nothing at all if I don't know what you are working on.

Customer: replied 11 months ago.
Ok hank, i understand. Night will be fine but can you call me so that you can get all the info you need? I sent a picture of the data of the generator. Hope you got it. It is a 65 k generac which came installed in my motor home. If you can call tonight, u will pay the extra 29 to get this issue resolved quickly. Thanks hank, al.

All I need for now is the model number and serial number of the genset. It is on the data tag.

Customer: replied 11 months ago.
Were is the data tag located?

It will be on the genset itself. Exactly where depends on which model it is.

Customer: replied 11 months ago.
I will do the best i can and esend you a picture of all the data on the generator

I don't need a picture.

All I need is the model and serial numbers.

Customer: replied 11 months ago.
Model 90112
Serial 097007

About how old is this thing?

I can not get the model number to come up at all, and a Generac serial number has been 7 digits long for at least 20 or 30 years. I have never seen a 6 digit serial number - and I've been a Generac tech for 15 years.

Can you get a picture of the entire unit?

Customer: replied 11 months ago.
This is a 1991 newport cobra motorhome, if that helps any. Picture is attached

Ok, I actually know several sister units to this one.

I need you to do a procedure called the Fixed Excitation Test.

I have uploaded the instructions for doing it.

Please do test #3, and let me know the results.

Click here to download the test.

Customer: replied 11 months ago.
I van do the test tomorrow but i need to know where the AC output leads are so that i can put the meter on them. Also, is the regulator wires marked with #4 and ok, or do i just pull the 3rd and 4th wires out ?

The wires at the voltage regulator are marked.

The AC leads are the wires that the 120V comes out from.

It is easiest to just test at the input to the circuit breaker, with the breaker shut off.

Customer: replied 11 months ago.
Ok Hank, i will give it the test tomorrow. Once i open the compartment where the regulator is and where the breakers are, ill send you a picture so you can verify that i am checking the right wires before i actually do it. Would hate to screw up and short the wrong wires and cause a bigger issue. Ill be doing it around 9 am tomorrow.

Unfortunately, I will not be available tomorrow.

I have to go visit my daughter in college tomorrow, and will not be back until very late.

Customer: replied 11 months ago.
Will Saturday work for you?

As I stated earlier, I do not have to be online for you to post. I will get your message when I log on.

I work my primary job this weekend, and work 6:30AM to 7PM.

I will be checking in sometime after about 7:45PM.

But just follow the instructions I sent to you. They make better sense once you get in there.

Customer: replied 11 months ago.
Ok. Will do but when i opeened the box that hold the regulator in it, i am pretty sure the regulator wires were not marked, but ill take your word for it and check it out. Enjoy your visit with your daughter, Hank.

Did you do the test yet?

Customer: replied 11 months ago.
Not yet Hank. Other priority came on the picture. Olanning on doing it tommorow. Will let you know when i finish. Hope you had a nice visit with your daughter.

I did. Yesterday was her 21st birthday. Had to go see her.

Customer: replied 11 months ago.
Awesome. You sound like a great dad. I have a 39 daugter and a 40 year old son. Still temember their 21st bd's
Customer: replied 11 months ago.
Hank, cold weather and rain has forced me to try to do the test on Monday. Will let you know


Customer: replied 11 months ago.
Hank, looking at the weather forcast, looks like i wont be able to do the test until Thursday. If i get better weather between now and then, ill let you know.
Customer: replied 11 months ago.
By the way, i dont have an extra 12 volt battery to use for the test. Can i just use the rv battery or do i need to disconnect it first from the rv in order to prevent other damage?

Just use the battery that is connected to the genset. You can pull the power from the starter solenoid, or the back of the fuse holder. There is no need to carry in an extra battery.

Customer: replied 11 months ago.
Ok. Thanks Hank


Customer: replied 11 months ago.
Well Hank, take a bow. I did the test and the light on the generator regulator came on and after i plugged the wires back into the regulator, i got power to the plugs. However, every time i try to run both AC units, the breakers trip. One at at time, no problem but together and the breaker trips. With a 65 k output, it should be able to handle both at the same time right?
Customer: replied 11 months ago.
By the way Hank, what did i do to cause this so i never do it again and what exactly did i do to repair this? Was it providing that 12 volt boost to the stator which got the regulator jump started?

Yes, a 6500 watt genset should run both A/Cs with no problem.

If it is tripping the breakers on the genset, it can only have a few causes.

From least likely to most likely, they are:

Bad breakers on the genset

Bad A/C units

Genset not producing enough voltage

Too many things on in the RV, besides the A/C units.

Customer: replied 11 months ago.
Ok. But each AC works fine on its own so doesnt that do avay with the AC's being the problem? I also did not have anything else on except the AC so too many things being on was not the issue. So i am left with possible bad breakers or too low of voltage. What is the voltage output supposed to be and how can i check ot and raise it if it is too low? By the way, please charge me for my first issue of not getting power and if you need to charge me for this new issue, just let me know.

The genset needs to be putting out 120 - 126 volts, with no load on the unit.

The best place to test is at the input to the circuit breakers, with the breakers shut off to prevent any outside interference.

Customer: replied 11 months ago.
Ok. Ill check ot in the morning. If its too low, what can i do to raise it to 120?

That depends on what the actual reading is.

Customer: replied 11 months ago.
Ok. Ill try it in the morning and let you know. As far as where to check, i have a red wire coming out of one breaker and a black wire coming out of the other and each breaker has 4 black wires ging into them. Where do i hook up the meter for the reading?

ON the input side of either breaker.

Customer: replied 11 months ago.
Ok. Two black wires go on one oole of the input side and two other black wires go to the other pole. Ill put the meter negative on one pole and the positive on the other pole and rverse them if i get a negative reading. Ill contact you tomorrow. Thanks Hank

No, you have to test from the breaker to neutral. There is no reverse polarity with AC.

Put one meter lead on the breaker, and the other to neutral.

Customer: replied 11 months ago.
Oh great. Where is nuetral. Boy i feel like a dummy

There is a stud on the side of the panel in there that contains the neutral and grounds. It will probably have 6 or 8 wires attached to it.

Customer: replied 11 months ago.
I thought those were all the grounds for the unit since they are all bolted to the body of the panel.

That is also the neutral bus. This unit has a bonded neutral.

Customer: replied 11 months ago.
Hank, im learning a bunch of new terms. "Nuetral bus". Cool. Thanks ill do it in the morning. You are Awesome.
Customer: replied 11 months ago.
Bad news hank. Today when i went to check the voltage, the red light on the regulator did not light up. I ran test 3 again but this time, the light only came on when connected to 12 volts and when i rehooked up the the wires on to the regulator and restarted it, the light did not come on. Tried test 3 several times but no change. I sent you two pictured of the panel area and the breakers. I have taped off the breaker wires to assure they dont ground when i screw the panel cover back.
Customer: replied 11 months ago.
Any thoughts of what to do next hank?

I actually am a certified Generac technician - I do not need all those pictures.

Since the generator is producing power when you apply 12V directly to the brushes, just not on its own,, the problem is a bad voltage regulator. You will need to get a new one.

Customer: replied 11 months ago.
When i touch the 12 volt lead to the other end of the of the positive 3rd wire coming off the regulator (instead of disconnecting it), the regulator loght comes on and stays on and the generator works but as soon as i turn it off, and then start it again, the regulator light does not come on again until touched by 12 volts. So where can i get a regulator and how much are they?

That wasn't what you explained in your last post.

Remember, I can't see or hear what is going on, and only know what you tell me.

What 3rd wire are you talking about? What is the number on the wire?

Customer: replied 11 months ago.
Its the "wire no 4" identified on the test. Rather than disconnecting it from the regulator, i followed the wire to its other end and just touched the 12 volt lead to it and the regulator light came on and stayed on and tje unit worked fine until i shut it down. Then i had to retouch that end connection again with 12 volt leaf ,after turning on the generator, and once just touched, the regilator worked.

Use a voltmeter and test wire 4 for 12V while the engine is cranking.

If it does not have 12V, follow it to the next device. The next device is the Choke Module. It will have (2) wires #4.

If you do not get 12V at the VR, check it at the CM while cranking the engine (leave it connected). Do you get 12V here?

At the CM, there is also a wire #15. Test it for 12V while cranking the engine. Does it have 12V?

Customer: replied 11 months ago.
Hank, i have no idea what you are telling me. I dont know what a CM or VR are. I sent you the picture not to doubt your ability as an expert but to share a common picture so that you might be able to tell me what to do via pictures. Nothing on the unit panel is identified by a name. I guessed at what must be the voltage regulator by looking up regulators. I am doing my best but i get the feeling i am frustrating you. Also, i amnot the best texter in town, hence why i didnt mind paying an extra 26 to explain verbally but you were not able to call.
Customer: replied 11 months ago.
I assume VR is voltage regulator. But i dont know what CM is

CM is Choke Module, as I explained above. Yes, VR is Voltage Regulator.

Just follow the wire 4 from the Voltage Regulator to find the Choke Module. It is the device to the left of the Voltage REgulator.

Customer: replied 11 months ago.
Ok. CM choke module.

Don't worry, if I throw an abbreviation out there, it will not be out of the blue. I will have spelled it out in the post.

Customer: replied 11 months ago.
Ok, ill check them tomorrow. Sorry for the frustration. I dont beleive either is getting 12 volt the VR nor the CM are getting 12 volts without being introduced by me, but i will check themm. How do i find wire 15, they are all blue with no id on them at all?

All of the wires are numbered with stenciling on the wire.

Wire 15 will be in the middle of the 5 positions on the CM.

Customer: replied 11 months ago.
Thanks hank. Ill do it tomorrow. Get some rest. Ill get my magnifying glass out to read the stencils. My glasses havent helped so far.
Customer: replied 11 months ago.
Wire #4 from VR connected to VR but not to CM = 0 volts at cranking.
Wire #4 connected to VR and CM with testing at crank at the CM duel wires=.08 volts.
Wire #15 connected at CM while cranking=11.09 volts
Customer: replied 11 months ago.
Also, as mentioned yesterday,when i provide the initial 12 volts spark only, at the CM connection of wire #4, the regulator light goes on andthe unit runs fine.

Ok, the problem here is that the CM is not providing field flash to the VR.

Power goes in to the CM on wire 15, and is passed to the VR while cranking. Your CM is not passing the power, so the problem is a bad CM, not a bad VR.

Customer: replied 11 months ago.
Where can i buy a new CM? Also, when i initially shorted the panel and the fuse blew, could that have caused the CM to go out or did it just die on its own?

You can order one through any Generac dealer, or from this website:

Customer: replied 11 months ago.
Lastly hank, what is the name of the solinoid with a plunger that actuates the choke on the carburator? One of the wire attacthment (what wire #06 attaches to) is loose and i probably should replace that as well.

That is the Choke Solenoid.

Customer: replied 11 months ago.
Can i get the choke solenoid at the same site?

The part number for the solenoid is 044128. It is available at that site.

Customer: replied 11 months ago.
Awesome Hank. Ill order both and when installed, ill contact you back with the final results. Thank you very much for your help hank.


Hank F. and 3 other RV Specialists are ready to help you
Customer: replied 10 months ago.
Hank the parts came in and i installed them and all os good. thank you for your time and patience. I left tou a small tip of $20 as a token of my appreciation. I wish i could leave you a $1000.00 tip, but i cant. Take care Hank

Good deal. I' glad it is fixed.