Portable Generator Project

[D45]

For a hobby and side money, I usually scroll Facebook Marketplace looking for portable generators that are cheap and need some TLC. I probably fix and flip 30-40 per year.

I recently stumbled on this beast, that the original owner paid $2,300 for and I bought it for $120!!

Generac 10,000W
Briggs and Stratton 19hp

It has nice features like the wheel and handle kit, spin on oil filter, and electric start

It doesn't have any rust and was stored indoors. I believe it is a 1999 model year.

The motor starts and runs good and the tires aren't dry rotted and hold air

The bad: Doesn't produce electricity

The capacitor(s) are either blown or the magnets in the generator lost power

I plan on doing an oil change with synthetic oil and installing a new oil filter, new spark plugs, and a new air filter

I need to remove the battery and see if I can get it to hold a charge, or buy a new one

 

[D45]

It has a nice variety of outlets

2 - Standard 120V 20amp
2 - Nema L5-20 120 20amp
1 - Nema L14-30 / 120V 240V 30amp
1- Nema 14-50R / 240V 50amp

Also has idle control switch and a 12V DV battery charge plug

 

[Jswain]

I did that during COVID and still do occasionally. Average purchase price $50-75, usually nothing but a few hours spent cleaning carb & wiping off unit, changing oil, clean or change spark plug and average sale $350-400. Canadian dollhairs not USD

 

[D45]

This machine takes two capacitors
25mF
450V
PN #B4914

These capacitors are around $50 each for oem Briggs!!! I want to look and search for a cheaper generic version


Generac # 65787 is for the 12V battery charging cord. This is around $20-$25

 

[D45]

Yes carb swaps are usually a solid 85% fix for neglected machines and are easily found for $20 on Amazon

 

[WildBill]

I also buy and sell a decent amount of generators among other stuff, I've read about generators sitting so long they lose their charging field or something, so you have to plug a drill into them and spin it by hand to get them working. Anyone ever experience this?

 

[D45]

Yes...... I've used a larger 12V car battery to recharge the magnets while it's spinning and running

I've never tried the drill trick

 

[mike93lx]

I also buy and sell a decent amount of generators among other stuff, I've read about generators sitting so long they lose their charging field or something, so you have to plug a drill into them and spin it by hand to get them working. Anyone ever experience this?

Yes my father had to do this on a generator. One of the reasons why I make sure to run mine with a load at least once a year, preferably twice, if it doesn't get used otherwise

 

[WildBill]

Yes...... I've used a larger 12V car battery to recharge the magnets while it's spinning and running

I've never tried the drill trick

Interesting, do you just connect it to the 12v output or?

 

[D45]

Yes my father had to do this on a generator. One of the reasons why I make sure to run mine with a load at least once a year, preferably twice, if it doesn't get used otherwise

Yes it needs to be ran with a loaded current/draw attached

 

[redmondjp]

If you are working on generators, you absolutely must watch James Condon on YouTube. You will learn everything you need to know about repairing generators. He goes through checking windings, regulators, he does a soup-to-nuts job showing you how to test everything and how to fix it.

Here is his channel: https://www.youtube.com/@jcondon1

 

[theoldwizard1]

Anyone trying to repair an old generator needs to watch a few episodes of James Condon's YouTube channel. This guy is a wizard at generator repair.

First, get a GOOD multi-meter (Fluke NOT required). One that reads below 1 Ohm. From the 240 outlet, check each hot leg to ground. It should be open (infinite). Now check each leg to neutral. These sould be low, maybe a couple of Ohm, but the reading should be equal.

Pull the cover off the generator. Check the resistance across the slip rings and then the brushes. These 2 reading should be equal. If not, bad brushes or dirty slip rings. Also check each slip ring to ground and neutral. It should be open (infinite).

All of this is covered in James's videos. So is recharging the residual magnetism.

 

[ihateminimumwage]

Specs for a slightly earlier model but should still apply:
Generac 9801-0, 1 / Craftsman 32682
Rotor 14.8 ohms
Stator 0.148/0.148 ohms
DPE 1.70 ohms
BCW 0.17/0.15 ohms

 

[micromind]

I also buy and sell a decent amount of generators among other stuff, I've read about generators sitting so long they lose their charging field or something, so you have to plug a drill into them and spin it by hand to get them working. Anyone ever experience this?

It's called 'flashing the field'.

It's simple, just apply some sort of power, either AC or DC across one of the outlets while it is running.

It doesn't take much but if you're using something like a battery, do it quick. Just blast it for an instant......the reason is because once the field is established, the gen will go to full voltage and current output. If the battery is still across the outlet, bad things will happen........

 

[RTM]

Dang, I am doing the carb swap on mine now, a Generac 4200 or so. Forgot to shut down correctly after a short unplanned usage after a correct storage shutdown, had jelly in the carb bowl, and the needle valve was frozen, breaking the float. New Carb off ebay arrived quickly. Will be installed this weekend. Hopefully no other issues, not run since last April or so.

Not flipping mine, getting ready for the impending bad weather PGE power goes to @#$%

Post swap edit. It all worked well, once I hugged all the parts together, lining up the air cleaner housing, choke lever, two gaskets while I put the two carb holding bolts in place. New air filter arrived yesterday.

 

[u3b3rg33k]

It's called 'flashing the field'.

It's simple, just apply some sort of power, either AC or DC across one of the outlets while it is running.

It doesn't take much but if you're using something like a battery, do it quick. Just blast it for an instant......the reason is because once the field is established, the gen will go to full voltage and current output. If the battery is still across the outlet, bad things will happen........

probably a great use for a run capacitor. charge it up to [pick a voltage], then drop it across the line. won't explode.

 

[honcho]

to the OP, sounds like a great deal if you get it working without too much additional money. Unfortunately, my experience with Generac generators in the mid-1990s was disappointing. The only ones we had worse experience with was with smaller 2-4kw coleman models. Admittedly, we were using them hard but it was never the engines, it was bearings and electronics associated with the generator heads.

 

[bcschief]

There are some really good videos on You Tube on generator repairs.

 

[D45]

Even if the generator head is bad, I'll have a good 19hp horizontal shaft engine to keep or sell

 

[D45]

This machine takes two capacitors
25mF
450V
PN #B4914

These capacitors are around $50 each for oem Briggs!!! I want to look and search for a cheaper generic version

Amazon and eBay has capacitors with these specs for $9-$20 each

I need to measure the stock B4919 size to compare

 

[StillTooManyHobbies]

Also check the brushes if it has them. I picked up a Troy-Bilt 6250 running watts for cheap from Lowe,s and it only needed brushes to be putting out voltage again.

 

[D45]

I'll take the brushes out and inspect them

It's around $22-$27 for this part

Briggs & Stratton 66386​

Brush Holder Assembly

(Superseded to66386GS)

 

[redmondjp]

Even if the generator head is bad, I'll have a good 19hp horizontal shaft engine to keep or sell

Bzzzt, sorry . . .

Most of these engines utilize a tapered output shaft that directly engages the generator rotor. In order to make it a useful motor for another application, you're looking at replacing the crankshaft. That kills the deal unless someone needs it for another generator.

 

[D45]

Correct generators used tapered shafts

I've used shaft adapters for $20, with good success

I've also sold just the engines to people that need replacements for their generator

I'm very hopeful this entire unit will be able to be repaired for under $100

 

[theoldwizard1]

Bzzzt, sorry . . .

Most of these engines utilize a tapered output shaft that directly engages the generator rotor. In order to make it a useful motor for another application, you're looking at replacing the crankshaft.

Any decent machinest can make a taper to non-taper adapter. It would require a bolt to keep it attached to the crank.

Also, if you are willing to disassemble the motor, the crank can be turned down straight and a key way cut in.

 

[D45]

I can access the generator motor brushes pretty easily

However, the two capacitors for the generator motor are going to require some more disassembling because of their location

I'm going to work on this alot this evening

 

[D45]

Also check the brushes if it has them. I picked up a Troy-Bilt 6250 running watts for cheap from Lowe,s and it only needed brushes to be putting out voltage again.

Well here is the motor brush assembly

One is functional with sliding spring pressure and the other is locked in place and not moving (wasn't even touching the motor shaft)

Briggs & Stratton 66386GS Brush Assembly Holder​

Ordered it on Amazon for $20.99, will hopefully be here tomorrow

I also took the battery out and it's on the 2amp trickle charger. I'm not too hopeful, but it's worth a try

 

[Sumboodie]

I had a similar one i bought at auction. Had a hard time getting $250 for it. Probably should have kept the Red Top battery.

 

[D45]

I'll wait off on the two capacitors until the motor brush assembly is installed and I determined if this fixes the no power output issue

The electric start battery is WP18-12

12V18ah

$39.99 on Amazon

I won't worry about the battery until I fix the power output issue

 

[D45]

Brush Assembly should be in today

I'm hoping the power regulator isn't cooked, because it's a discontinued part.....but there are two listings on ebay for $175!!

Briggs & Stratton Regulator - Power #BS-92769GS​

I have seen online businesses offering to repair circuit boards and such for $100 and under

 

[rust in the eye]

Another Y2K generator.
I've stumbled into a few of them. Fools in a panic bought them (and toilet paper*) December 1999, gassed 'em up then often left to rot.
* WTF is it that when threatened with disaster so many peoples' thoughts immediately go to wiping their ***?
@ OP Last week I dragged home what is the little brother to yours, a 5500xl with a 15 hpGN410 engine. Is there a way to make these things easier to pull start? Man this thing is a bear to pull the rope. I'm wondering if there is fault in the gen section causing it to resist turning. Do the mag fields de-couple when starting? Clearly the gen section is not my forte.

 

[D45]

Some do have high compression for sure

I always change to synthetic oil and make sure the plugs and air filter are new

If they sit, the air filters do deteriorate and break down, not allowing the engines to get enough air!! I have see piston rings develop rust spots also

Start it and let it run for an hour to get everything really hot to lubricate everything and burn away any rust. Then change the oil.

 

[D45]

Motor brush assembly was delayed, supposed to be delivered today

I'll get it installed tonight, should take no more than 20 minutes and then I'll test for generator power output

 

[D45]

Arrived and installed

Still no power output at the outlets

I wonder if I could have the #92769GS power regulator checked somewhere

Or if I should try reflashing the generator first and/or inspecting the capacitors

I've had capacitors go bad before in 5kw generators

 

[D45]

I believe I have to dig into the generator head to access the two capacitors

B4914GS

 

[PMD1966]

For a hobby and side money, I usually scroll Facebook Marketplace looking for portable generators that are cheap and need some TLC. I probably fix and flip 30-40 per year.

I recently stumbled on this beast, that the original owner paid $2,300 for and I bought it for $120!!

Generac 10,000W
Briggs and Stratton 19hp

It has nice features like the wheel and handle kit, spin on oil filter, and electric start

It doesn't have any rust and was stored indoors. I believe it is a 1999 model year.

The motor starts and runs good and the tires aren't dry rotted and hold air

The bad: Doesn't produce electricity

The capacitor(s) are either blown or the magnets in the generator lost power

I plan on doing an oil change with synthetic oil and installing a new oil filter, new spark plugs, and a new air filter

I need to remove the battery and see if I can get it to hold a charge, or buy a new one

Took a generator repair class years ago. Instructor said capacitors loose power when not used. He showed us how to remove the capacitor and recharge it with a D cell battery and a short piece of wire. Remove the capacitor, and touch both terminals for about one second.

 

[D45]

That's a great tip thanks

Looks like the capacitors aren't readily accessible on this unit as most others that I've worked on

Time to dig in

 

[D45]

Where could the two capacitors be?

I've only seen them in two places:

behind the generator head end housing

behind the panel for all the outlets

 

[D45]

That diagram I posted above is for the 09801-4

I have some 09801-1, and I don't see any capacitors in the parts diagram

 

[ihateminimumwage]

IIRC those have a voltage regulator, not caps. PCB behind the metal screen on the back plate of the gen head. Been a long time since I worked on one though.