Voltage Regulator

[roachcoach]

I have a 75D Generac generator and may need a new voltage regulator. I was hoping someone could tell me where it was located. I looked in the owners manual but couldn't find it.

[gsf35099]

I was about to buy a new one a month ago and said, it runs to good not to run it until it dies. Ha. I've got over 2400 hours on mine & it's purring like a kitten again.

Pretty sure your rig is set up like mine where the wiring for the gene is actually set up for an Onan and there is an adapter to the Generac. You will see the adapter plugged into the gene to another plug. When mine finally dies, I'm switching to Onan Cummins. But for now it's been cheaper to repair & it's running great.

Not running smooth concerns me a little, but it may be the oil your running. Most of the time I'm running mine in 100+ degrees here in central Texas and it cruises with both AC's just fine. Two weeks ago I ran for 3 days & temps were 106 for the highs.
For higher temps you need to run 15w/40. I run that all the time even in freezing temps and have never had a problem.

Overheating is a known issue with these models from what I have found. I Have found the shielding is a requirement to be on properly to make sure there is sufficient airflow past the radiator & having a clean air filter. Plus when it's hot out side, opening the front hood helps.

I found eBay has the best deals on new VR. Search for part number 083048 or 83048

Good luck & keep us informed on how it goes.

[roachcoach]

Yes that's what I mean about the rpm's and the engine is not running smoothly . A couple of weeks ago I had some work done on it , changed the thermostat and cleaned up the radiator. It was running smoothly and left a happy camper. While in Yuma the temps got up to 108 and the generator shut down . So we decided to only run 1 AC and it ran good. DW and I were talking about buying a new generator, maybe a different brand but after communicating with you I decided to rebuild it.
BTW where is the best place to buy VR and thanks for all your help.

[gsf35099]

Are you hearing the engine change tone under a load?
Is that what you mean by RPM's going up & down?
Is the engine running smoothly?

I'm assuming all the maintenance has been performed, coolant good, oil, & filters. There is a small inline diesel filter on the driver side at the bottom before the fuel pump. That one IMO is a PITA to get to because the top & side covers have to be removed.

There are two belts on the gene.
The one on the drivers side is the water pump & cooling fan belt.
Passenger side is the power belt.
Each have an auto tensioner & I did have to replace the power belt one before because it was allowing the belt to slip. Would squeal.
Make sure the belts are good & not slipping especially the power belt.

I'm not an expert at it yet, but that is a big swing in volts & if it were me and the gene is running smooth, the belts look good & not slipping, I would replace the VR. I did have a problem ~5 years ago with voltage problems & the Generac dealer working on it replaced the VR to fix it.
If you do decide to replace the VR, there is a POT on the VR to adjust the voltage output. Takes a very small screwdriver.

[roachcoach]

I noticed that it was sounding like the rpm's were going up and down so I checked them and it was actually fluctuating between 110 and 130. I was going to try adjust it but my mechanic said that was a big difference in voltage and probably raise it too high.

[gsf35099]

Well, I was troubleshooting the darn thing shutting down after running for a while. While doing that I noticed my voltage was dropping to 115v when both AC's were on and I didn't like that, so I wanted to see if the voltage drop had anything to do with the shutdown.
Turned out it did not, but the new VR did hold the voltage much higher with both AC's on at 119v.

What kind of problem are you having? I tore into my generac pretty good and know it pretty well in my opinion. 🙂

[roachcoach]

gsf35099 wrote:
I have the same gene and just replaced the voltage regulator.

It's located on the left front (passenger) side towards the bottom. There is a panel there that covers the electronics. Be careful not to damage the gasket when removing or replacing. Really a simple job and was easier for me from underneath after removing the bolts on the top from the front. Is a little tight with our models.

Sure wish they would have made the gene slide out. I'm Actually looking into modifying my RV to allow this through the front.

If you need some pics, let me know. I can post some.

What was your generator doing that you replaced the VR?

[gsf35099]

I have the same gene and just replaced the voltage regulator.

It's located on the left front (passenger) side towards the bottom. There is a panel there that covers the electronics. Be careful not to damage the gasket when removing or replacing. Really a simple job and was easier for me from underneath after removing the bolts on the top from the front. Is a little tight with our models.

Sure wish they would have made the gene slide out. I'm Actually looking into modifying my RV to allow this through the front.

If you need some pics, let me know. I can post some.

[roachcoach]

As I stated I could not locate the where VR is actually located after looking at the manual . Last week I had a mechanic work on the generator thermostat and he did a good job while I was in Tucson but this is something else that happened recently.

[MountainAir05]

You were given a link to the manual last week, it there. You might be better ahead to take it to a Generac service center to check it out. You might want to print it out. Engine still might have to be adjusted. Your are going to need it.


https://www.jackssmallengines.com/Generac-Parts-Lookup/Generators/4270-0.pdf