F3 error code on Briggs and Stratton generator ... voltage.

OK.

Please take what I am about to say with an open mind. I am not trying to offend anyone, nor put anyone off.

I have been a generator technician for 20 years now. I have seen WAY more than my fair share of "techs" who have no idea what they are doing - and I can give you a perfect example (besides yours).

My neighbor directly across the street had a 20 kW B&S genset installed at his home last October - brand new. Last month, it started showing the F3 - Low Voltage code. 2 techs showed up to work on it. I just happened to go over there while the "techs" were there, as I needed to ask my neighbor a question. These techs were getting ready to order a new fuel regulator, even though the engine was running just fine. Their reason? Because "the book says a bad regulator is a possible cause of low voltage". Yeah, right. After I explained to them that a bad regulator causing low voltage would mean that the engine is running to slow to create voltage, I asked them what the gas pressure was. They had no idea, because they didn't have "one of those tools to measure water column". These guys were supposed to be techs, but they didn't even have a manometer (the tool used to measure gas pressure. I promptly walked home, literally straight across the street, and brought back 3 manometers so they could have their choice of which one they wanted to use. Big wonder, the gas pressure tested just fine. I asked them if they had tested the generator (rotor and stator), and they had no idea how to test them. I had to show them how it was done. It took all of about 4 minutes. The problem was a bad brush - a $15 part. Unfortunately, I could not do the work, as my shop is not a factory authorized B&S center, so I can't do their warranty work. These guys didn't even know how to change brushes, so however they did it, they ended up getting B&S to replace the entire genset. All over a $15 part that takes about 2 hours to install.

It sounds like you are having the same issue - "techs" that really aren't.

Any tech that tells you that rotors and stators can't be tested is a tech you need to steer clear of. Rotors and stators are easy to test. With 1 exception, all you need to test them is a multimeter. Although they can and do go bad, rotors and stators are usually the very last things to go bad. It is pretty rare for them to fail. It is almost always something else. A full system test can be performed in 30 - 45 minutes.

As you have already noted, this part is no longer available. I have no idea where you came up with that Generac part number. That is not a valid part number. And this is a B&S unit, not Generac. Generac has nothing to do with it, and I seriously doubt you will find a Generac part that will fit.

My suggestion to you would be to find a different tech, or just test the system yourself, if you think you can handle it and have a good multimeter.

Did you mean 40 ohms? If so, then yes, the stator is bad.

With the part not being available, you are only left with 2 choices - a new generator, or a repair of the old parts.

You can have a stator rewound at any shop that rebuilds electric motors. It is somewhat costly, I would guess in the $600 - $700 range for yours, but is still less expensive than buying a new genset.

However, that leaves you with no warranty on the rest of the unit. Even with a new stator and/or rotor being rebuilt, there is nothing to say that something else won't go bad in 2 weeks, 2 months or even 2 years.

But on the other hand, a new genset will cost a pretty penny - but have a full warranty.

As far as Generac goes, it is the brand I recommend (yes, I am a certified Generac service center). But Generac has a much better service and parts network than does B&S.

B&S has never owned Generac. They have always been separate companies. There was a time about 20 years ago that Generac got out of the portable business, and partnered up with B&S to build their portables. Generac provided the technology, and B&S provided the work. B&S put Generac labels on these units. But that partnership only lasted a few years, and now Generac is again producing their own portables.

But for home standby units, B&S has always been all B&S, and Generac has always been all Generac.