Two Generators No Power Output - Same Model, Same Problem? 

I've watched hours and hours of your videos, and you've educated me not to be scared of pulling these apart. Bought two gennies both none runners and them working within half an hour, thanks to your tutorial. One I had to dial in the running speed to get the voltage where it was right.

Pretty crazy both generators had the exact same brush failure, probably just poor quality manufacturing, nice work James!

Something else to check there. I've had that same fault occur with a certain brand (looking otherwise identical) where the ball bearing in the tail housing had started to spin. The bearing itself was still ok, but the outer race spinning had allowed a small clearance to develop, probably loosening when the case metal heated up in use. That clearance then allowed the rotor and slipring to chatter which caused the brushes to bounce and arc, and then overheat. Replacing just the brushes became a temporary fix before discovering this. Your slipring shows the same chatter marks. I found a loctite bearing retaining compound that cured the problem, I also pulled the bearing itself back slightly on the shaft, that allowed it to index on the original bore while the loctite filled the remainder. None have come back since adding this repair to the original brush replacement. An alternative would be to over bore and sleeve the housing, if I was doing my own (with no cost limit) I'd do it that way. Cheers.

Hi James, I would make two suggestions. One, attach your drill to the rotor shaft and turn it slowly that way, then use some 400 or 600 grit wet and dry paper on the slip rings. That way you'll get the grooves flattened out. Follow up with your scotchbrite. As to why these failed it's the material used for the brush holder. It needs to be Bakelite or a similar material. The plastic they've used is too easily melted by heat. They will fail again. Running 3000 watts from these is too high. Despite being listed as 3200 watts that would be for a very short duration. Somewhere it probably lists 2500 or even 2000 watts as the continuous power. Just my observations. Thanks for the video.

James, the reason why those brushes failed so quickly is because of them being misaligned onto the slip rings. I'll send you a private message with a picture describing what I'm talking about but you may want to use an inspection camera to make sure the brushes are sitting directly on top of the rings. If only a portion of the carbon brush is on the slip ring it creates a bottleneck for the current to go through thus why it got hot.

They should've made the brush holder out of Bakelite plastic. What I see is likely ABS with 30% glass fibers. Strong, but not heat resistant. Bad engineering design. That's why ALL of them will develop this fault in time.

Another problem that can happen with these kinds of generators is they become degaussed and need to be flashed. These generators don't have permanent magnets, they depend on electromagnets to provide the static field that the rotor field moves through, to generate power. There's usually a small bit of magnetism in some iron that provides enough of a field for it to start generating a bit of power for the static field coils, which then provides a strong enough field for the generator. What happens is sometimes that bit of magnetic iron gets degaussed (ie. all magnetism removed from it), so it is no longer magnetic, so the generator can't start generating power to generate a field which then makes the main power. The way this usually happens is if you turn the motor off while the generator has a load attached, or if it runs out of fuel with a load attached. You should never start or stop a generator when it's under load, because of this. The way to fix it is to "flash" the generator. You can do this by either using a car battery to put a short pulse of current through the coils WHILE the generator is running (connect and disconnect it really fast between the active and neutral of the generator output). Another potential way is to have a corded power drill plugged in while the generator is working (but not generating power), then quickly spin the drill - the idea is that spinning the drill will induce enough current in the generator's coil to provide a start field for the generator. I found the car battery method to be the most reliable, but it is dangerous - you only want that to be connected for a very very short time. There's a few youtube videos on "flashing" a generator which probably explains it better than this.

You said it at the end, James. Either bad brushes or bad slip rings. Using substandard brushes is easily remedied. Substandard slip rings are a life-limiting flaw that will finish off a good rotor before its natural life comes to an end. We all bemoan poor quality components in our products do we not?

I would say you can see chatter marks in the original machining of the second generator. Probably the original failure mode.

James, you are a master. I'll probably never stick my hands in a power head, but I thoroughly enjoyed watching you. I know I could if I had to. You're so knowledgeable and calm.

I noticed that they only use one of the possible two bolts to hold the brush carrier - a few cents saving that could allow the brushes to mis-align and cause the heating and failure. But my bet would be poor initial quality of the slip-ring surface which adds to the one-bolt problem in causing brush heating. Drill and tap for that second fixing bolt!

at 10:35, I would've spun the rotor using a socket attached to a power drill to turn it, while using a 400-800 grit sand paper to shine the brass rings.

Good job(s) Jim, I take it you have been assembling a database of parts used, ohms readings and failures encountered. At this point your knowledge base must be getting quite extensive. Keep up the good work and enjoy the holiday.

Easy fix and a cheap 8 dollar part. I love those. Wish all my repairs were that easy.

I'd would have my 20v drill slpin it over that way you getting it clean without the hassle. I'd feel the roughness of the slip ring and use a very fine piece of whetstone to remove the worst of the roughness then go 1000 grit dry sandpaper then followed with a 3000 grit wet sandpaper then clean it with a lint free cloth rag dipped in lacquer thinner then reassemble with new brushes and holder it should run till the motor is wore out without anything except possibly brushes if ran often enough

I've heard of the capacitor being faulty and not storing enough to excite the armature windings, the machines you fixed must have had defective brushes from the factory if they weren't able to clean those rings through use. Good diagnosis.

That's what happens a lot in a throw away society unfortunately. Cheaply made parts and cheap labor. The companies make more money and don't back their products. Everything ends up in a landfill and you have to buy another one.

very much interesting, thank you.

This fix works for me. But I know very little about generators so all I can say is great information for me. I think the customer will be very pleased even if the brushes have to be changed again. Thanks for the videos.

This is why the companies should've stayed with the ceramic brush holders, not throwaway plastic. Planned failure.

My neighbor has this exact machine. About 18 months ago we had a bad ice storm and power was out for 12 days. About day 5 he brought it to me with this exact problem. I buffed the slip rings heavily and works great

You can also put high temp graphite lube on the brush blocks where they slide in and out of the plastic holder so they mate up smoother with the slip rings.

The lathe has left marks on the slip ring ! Like a thread. This increases friction. And it's getting too hot!

I had a thought when you were cleaning up the slip rings: When you have a bad rotor, you might cut up the slip rings and find out how thick they are. If they are relatively thick the next time this happens you can use something more aggressive (grades of emery cloth) to make sure the rings are really smooth. Another excellent video. Thanks!

Very educational. As an aside, I had a royal pain on a Hyundai HY7000 that was a nightmare from day of purchase (in fact the genny was 4 years old when "new") that would not start after 2 years of having to replace all sorts of bits that simply failed, like the tank float, the fuel valve, both wheels at different times, the digital display module (which has failed again.. Turns out the internal coil cell has run flat.. The module is No Longer sold as a spare part), It has run less than 20 hours in the 6 years I have had it. Turned out the latest starting issue was the magneto as it never ever started on the cord and was reluctant on the electric start. Now, for the first time ever, it starts on the cord. Shout out to generator Guru in the UK for having the spares Hyundai after sales in the UK said were unobtainable.

I've "fixed" so many old generators by doing the drill trick. Just plug in your drill and hold the button then grab the chuck and twist real good. Literally every time someone seen me do it they were in just disbelief lol 😂 like yep I'm a sorcerer I have lightning in my fingers

Watching your videos helped me on the weekend power went out had to clean carb on generator even though I ran it out of gas and drained the float bowl. Thanks

A small narrow honing stone, to clean and smooth the brushes, i do this with the engine running, After honing i use a piece of hardwood to burnish the slip rings, this removes any scratches and helps prevent arcing by creating a surface on the slip ring that is equal resistance any point overall surface, no arcing

Wow, what's the chances of 2 generators of the same make & model falling in your lap & both having the same problem... And a fairly easy fix too! I wonder if it would make sense to clean up the slip rings with a little emery cloth first & then polish them up with the scotchbrite pad obviously making sure to clean any grit off them when done. I've used this method on automotive starters without any problem. Nice job checking these out & quickly getting to the root of the problem!

I think the company must be notified.

Design fault. The brush box is thermoplastic instead of thermosetting plastic, eg Bakelite, which would withstand the temperature. The machining of the sliprings appears to have chatter marks. This would cause the brushes to bounce and arc until they bed together over time.

You get what you pay for. The generator was poorly manufactured as shown by the chatter marks on the slip rings when the rotor was manufactured. Also I would suspect the slip rings were either out of round or off-center from the axis of rotation or the rotor was not aligned to the engine shaft, that would cause the brushes to jump up and down 60 times a second trying to follow the slip ring surface. Also it seems the brush holder was made of a low melting point plastic and the brushes may not have been centered on the slip rings. The proper correction would be to mount the rotor on a lathe, measure the slip ring run-out and true the surface with fine cuts, then smooth with 400 grit wet/dry sandpaper and finish off with green Scotch-Brite. However, I do not think this model generator is worth the effort. Two generators going bad exactly the same way exposed a design flaw so I would keep a spare brush holder on hand like a spare fuse for when this happens again.

I think -- Factory defect. Same problem on both Gens.

I Googled the brushes after you diagnosed the 1st one and found it interesting that they're so omnipresent on the internet,,,, must be a chronic issue over many makes and models...

you didn't mention how you addressed the melted part of the brush holder. did you replace it? if so what brand?

18:30 More cheep, cheap chinese cheepie junk. They do not make, the slip rings, out of copper; also, the cheapest low quality carbon brushes. Get some, made in USA. i had an Xstream 3100 gen. IT had the brush holder, positioning the brushes, too far INTO rotor slip rings, the inside brush, was only half on the slip ring, with wear at a 45 degree angle. So, i shimmed it up ( tim the shim, coffee) with two small washers, between the housing and the brush holder; moving brushes about 3/32 inch toward the outer cover. Cleaned up slip rings, now makes ' juice'. Engineering from metric/english buggered up the Autocad engineers, in drafting the measurements. And, the assemblers didn't care.....typical chinese cheapies.

Well now we all know which dead generator will probably be an easy fix 😁 I think the REAL culprit is the brush holder being made of poor materials which could cause brush sticking and arcing, which adds heat causing more sticking and arcing etc. There could also be some misalignment between brushes and slip rings. A little either way could be fixed: shimming outward or filing the mounting surface thinner but you hit limits of the material strength. Best would be that doing that if needed, and better quality brushes if available (and they probably aren't). Being an easy and cheap fix, I'd recommend that anyone using these just replace the brushes based on use-time as maintenance, and having an extra usable brush-set on hand for emergency repairs. This is the kind of thing you encounter with low-quality cheap machines of all kinds, and it may be acceptable based on your usage and ability to do the fix. I've got a different cheap generator but now I'm going to pop the end cover and have a look at the brushes, because now I know this might be a potential problem 😉It's honestly something I never considered as most brush holders I've encountered were pretty stout, but I guess "cheapening" happens here too now 🤥 A good job as always James 👍

I'm watching this now, because I have what I think is an updated model of this machine. Mine is marked HomeLite, but looks identical to these, except that it has a digital voltage display. Works fine, but then, it's got less that 20 hours on it as I only use it for emergencies. I do run my 2 gens for 20 minutes every 2 months. Ok, continue to watch and learn, just in case! LOL *QUESTION* how difficult is it to order new slip rings and how difficult is it to replace them both?

That is strange both are doing the same thing. must be a fault in the making the making of them?.

When you said you wanted to ‘scotchbright’ the slip rings - I thought you were going to drive the generator shaft with a socket in a battery drill - I love the meticulous diagnosis on your channel - good watch!

Thanks for giving us something to watch, and a happy ending to boot.

Wow ive never seen you load one up that close to maximum rated power. 👍

I have 3 generators that are probably 20-30 years old and all of them work...stop spending money on modern garbage and buy a used generator lol

Jim: I learn a lot from your clear explanations and I might even tackle a job like this if I came across the opportunity. I have the engine side down. It is the generator side that I am learning from your content. Thank you. Do your space heaters ever get used to heat spaces, or are they basically for the purposes of providing known load for testing generators?

I cannot say I’m particularly impressed by the brush holder. Looks a pretty flimsy affair and certainly not very well secured. The very design of this would encourage the brush holder to slip out of alignment resulting in the brushes not running perpendicular to the slip rings. Very poor design.

What are the odds of getting two identical generators with identical issues that are identically easy to repair? Lol that’s awesome, great job!

The material the brushes are made from changes the resistance and causes heat build up.. the higher the resistance the higher the temp... good brushes DO NOT GET HOT and the brush holders dont melt.. you can measure the resistance of the brushes.. ALL GENERATORS ARE NOT CREATED EQUAL... you get what you pay for...I would not spend my money on something like that..GREAT VIDEO !

Congratulations on your "twins," Jim. Who knew that they would have the same problems. I passed up two generators at a local scrap yard. One was missing the carburetor, and the other one I didn't get a close look. The first was a rebadged champion unit. I suppose that they both could have been repaired given the fact that it seems that they were scrapped by an electrical contractor who was either closing down, or maybe just cleaning up the tool room. I got two ridgid 24" pipe wrenches, and they were fine, one forged steel and the other one aluminum, and the corded tools in their metal cases likely were fine too, though they appeared to be a bit older, like the Black and Decker reciprocating saw. It's a shame there is so much waste. I had my car this day and didn't want to mess up the seat, so I passed on the generators.

My friend has a 10kw that wouldn't start all of a sudden, very few hours , There was an inline fuse under the gas tank that had blown,,it was almost like they hide it on purpose.

The fact that you have with the same failure tell me that it is a faulty design and both will likely fail again. Should be a recall or at least an updated replacement part available.

We've seen this problem before, and it's almost always been on generators which weren't given any 'run down' time after running on a full load. It shouldn't happen at all, but it always seems to be on machines that have been hot, and not allowed to cool down before stopping. Another scenario might be on machines that have been overloaded, long enough to overheat, but not enough to cause a failure. Looking at those slip rings though, it seems evident that the machining leaves a lot to be desired.

This is just like your "double trouble" video from way back. 😃😃👍👍 Glad that it was an easy fix. But come on Jim ....only 24 mins? 😂 Looking forward to next week. Thanks as always for excellent content.👍👍😃😃

For the brush holder, how about using material built from Bakelite?

You could have driven the rotor with a battery drill while cleaning the slip rings.

James, I've had a few problems with brushes swelling I suspect with damp? Of course they stick in the holders and rapidly fail. This is a bit different as they are on power tools of different kinds.

Thanks for the video

First time I differ with James. On this particular situation with an identical problem, I would change slightly his fix. I would start the engine to clean the slip rings. When a situation like this particular one surfaces I would run the engine with sand paper instead of scotch bright. I would make sure both slip rings were completely smooth and clean and might use a new lead pencil with the eraser end on the sandpaper for two reasons. 1. To reduce probability of shock. 2. To hit exactly the spot on the slip ring being cleaned. He left roughness on one slip ring in each set. Dancing brushes will certainly overheat and in the future produce similar results.

What causes generators to stop making power? I have one for emergencies, I pull it out and start it occasionally. It stays covered with a blanket and a generator cover in the corner of my garage. What can I do to keep it in good working condition for when I need it? I only run non ethenol fuel and I don't keep gas in it, I turn the fuel off and run the carb dry before putting it away after starting it and letting it run for about 10mins or so with a fan plugged into it every few months.

Hi James! Thank you for your videos! For some reason, I am sitting and watching them all :) despite I got nothing to do with world of mechanics. I even fixed my Generac 5500 according to your instructions, believe me or not. Keep it up please !

Great, really enjoyed your video

your videos are always SUPER ! thank you

Thanks for a great vudeo again James , my thougts is that the brushes were not broken in properly and got overheated from start . Here is what im thinking and i dont know if i am wright , you should run the genny a tank on a quarter of load only to brake in the brushes and let it run 15-30 min after use to cool down. After that you can use it nomaly.

Excellent troubleshooting. I like that. Did you order brushes online or did you have a pile of spare parts laying around. Thanks for sharing

Hey, just a tip. Don't start a generator with a load on the power. Even that bulb could cause issues eventually.

Thanks! What info do you have on the Yamaha EF2800i? Mine is functioning perfectly fine, I'm just looking for tips and potential issues that will pop up when it is needed most.

Unless there's a MOD., I'd say this WILL happen again! Poor design.

Hi James great class mate nice to see you had twins with the same problems and a easy fix Its great when it works out that simple Keep up the good work James

I don't if you know about them, but they have these sticks thats have diamond dust in them used to seat new brushes in small motors. What I have done in the past is start the engine and polish where the brushes ride, just watch out for your fingers.

Yea those cheap imports, lucky that both work again, easy fix great video

Hello James, your video is very interesting, acquiring two equal generators with the same problem, suggests that the quality of the constriction of the brushes and of some elements, may be of inferior quality... thanks for your videos and the teaching to analyze and solve these types of problems... thanks... a big greeting from Puerto Rico 🇵🇷...

Great tip James

Nice job & even if they were just parts machines $75 was a bargain. I wonder if that's a design flaw or maybe those sliprings were badly machined.

A fun twofer for a Thursday morning. I think this is the first video of yours with melted bush holder. Something I'll have to keep in mind if mine ever fails. It may just been me but the second genie sounded like it was hunting.

You can really hear the throttle open up when you turn the second heater on! Seems like a nice snappy governor though. The thing I'm starting to notice with generators is that the newer ones tend to put out more stable power (AVR, fast governors etc.) but the build quality and longevity isn't nearly as good as the old heavy, loud things with no AVR and more sluggish governor. Though back when those were made, people weren't running nearly as much sensitive electronics with them.

I bought a new Honda EB3500X for $400. The owner said the engine was fried. I Checked spark, good, I Checked fuel flow, Not so good. I took off the fuel lines, carb and spark plug out ran 2 cans of carb cleaner thru everything, Wow Real Dirty. Cleaned all ports reassembled everything, Took Fuel tank off , 2 more cans of carb cleaner, put tank on and added 1 gallon gas. 1st pull and it was running smooth, checked all outputs, perfect. Checked Price on the Gen Damn near fell over. I couldn't believe I just bought a ( + - ) $3000. gen for $400. Found 2 on Ebay Not running for $1500. Been 3 years now and it still runs my welders just fine in the field. I do run all my Gens for about 10 to 15 minuets and use a grinder in each outlet once a week when sitting. Keeps the carb cleaned out. But you got a better price at $75.00

About ready to test clip of American made AP rounds on 2 junk harbor freight 9000 generators that didn't last a yr, both not worth repairing. STAY AWAY FROM THAT PLACE

Any ideas? I have a GX390 with a honda engine. Engine works excellent. At start up, provides 120 volts for 10-20 seconds then drops to 9-12 volts. I have replaced the AVR with no change.

Great Scott!! I mean, James😉😉 .... Talk about "Whack-a-mole" ..... that's eerie James. I hope it's not the start of an omen....

I have an ETQ generator 8250 that I got for $85. It had almost no compression. I believe the rings were shot due to cylinder wash( gas in oil) . I honed the cylinder and installed new rings. Once I got the engine running, it was not putting out any power. Low and behold my brushes were worn down(actually they were short and had jagged ends like they broke off). I received my brushes today. Hopefully that will fix the problem. I’m probably going to order an extra set to keep as a spare. I don’t want to have an issue when I need to rely on power during an extended power outage due to storms. Recently was out of power for over a week in Louisville ky. 😩

I won't bet a dime on these new brush holders! The brushes always get hot, and they always spark, more or less. This is their normal working condition. On the other hand, it is completely ridiculous for me to use thermoplastic material for brush holders - this is a guarantee of another failure that will occur again soon. In well-built brush holders, the brushes themselves are usually placed in metal holders constructed in such a way that they have enough surface to dissipate the heat generated by the brushes. These handles are attached to the insulating material ALWAYS with high resistance to temperature. In very good constructions - electrotechnical ceramics are used, in poorer ones - fiberglass in epoxy resin. However, I have NEVER seen such crap so far!!! Chinese shit not worth pulling out a screwdriver and wrenches. There is ONLY one way to reliably repair it: replacing it with a heat-resistant brush holder. Either buy a good one, if it is available for sale, or make it yourself from basis, which is unprofitable in my opinion.

Ha ha, same brushes problem on the two generator... Be serious, the brushes used are too small to collect 26 A (3200w/120v) without overheated and destroy the brushes's support ! As i can see, the collector rings are not copper... It is only a generator bad and poor design !!! You should have the same problem after running few hour !!

I bet AVR Calrify that voltage Regulator. remember those folks on your cars in the 60's and 70's? EDIT : Amazing what a 4 or 5 dollar part can do. We need to go back and not forward. lol

Brushes arcing.....burned up........could have been tasked to run too many appliances also = overloaded.

Where did you get the replacement brushes? HOW did you find the replacement brushes?

I have a scorpion SC2500 and it had no power output. I checked the AFR and Brush and no issues. On the panel it has a Voltage indicator and in that there is a little black screw. I twist tgat a couple of times and boom, power output. Hope this helps someone.

Decent video, well explained, but you may of heard this before, ...why would value your life at $15.00 using that piece of shit multimeter? You sound like an intelligent guy and why would use this tool that could fail miserably and result in electrocution? You don’t have to reply to this question btw. Life is to short to save money buying crap tools my instructors used to say.. Obviously the generators fall into the same category as your multimeter. Nice video though.

The gen set twins 😂😅😅😂

Those are high R. P. M. generators. They are not designed for long life. They are called single barren generators. Meaning, they are built to turn 3200 R. P. M. s. The only generators made to last are two barren, 1800 R. P. M.

James, informative as always. Question - Using "CRC electrical contact cleaner", spraying that on the armature help clean up the carbon build up? What about using fine steel wool or would it be a possibility of small particles of steel wool getting into the machine? Nice trouble shooting.

Actually like recalls on cars. One part failure due to assembly or contracted part. Slip ring turning would be a strange problem, but if those rings are replaceable, I would say, metallurgy is your problem with purity of material. Wear on those rings should be the same, but pitting would be a forging, a temperature mix of material not being hot enough, problem. I can see those rings being made in some Chinese guy's yard, with a coal fire and poor material proportion. There's not that many generators out there, that they had to go to a major foundry. Just my opinion, but if changing the rings is feasible, I'd change those too, or order 6 sets of brushes for future use. You never know how long they will be made.

Thanks for the great video as usual James. I look at it as a quality control issues that made the components at the factory or they sat and accumulated the corrosion? At any rate thanks for the almost tear down. Ed

I have a duromax xp 4000s that starts with no problem at all, I plug 🔌 in a 2 inch submersible pump, it pumps for like a minute then it loses power for like 30 seconds then over again, anyone have any i

Well, I think you've discovered a manufacturing defect of inferior quality in brush holders and slip rings.

I would have cleaned the armature/slip rings with some emery cloth on a block of wood/stick with a flat surface to help reach in there and hold the emery cloth. With the brushes removed and everything out of the way, I would start the engine. Then use the emery cloth to clean the armature/slip rings so they look like new. That should lessen future potential problems. I'm NOT telling anyone what to do or suggesting anyone do this. It's just what I would do.

I had a similar experience with the rotor on my motorcycle. The slip rings had what I would call divots that caused the brushes to chatter. Replacing the brushes didn't fix the problem and I had to change the rotor. I would measure the runout of the slip rings before I called it good. Perhaps a local machine shop could turn the slip rings on a lathe.

Just subscribed!! Awesome video, just wish you lived closer to me haha my Genny has the same problem slightly more complicated though it's a 15kv arcgen powermaker but you have now given me an idear what to look at to see if I can fix it, also putting a low voltage out but nothing like it should be so could just be the brushes on the rotor hopefully!! Would it be a possible cause off my welder genny not produceing the power it should also I rebuild the engine but it slows right down when you turn the amps right up and really labers think it's more to do with the alternator though

Before doing all that resistance testing, i would have checked the voltage going to the brushes and slip rings, If no voltage from AVR, then put 12vdc on the brush terminals snd start engine, should get around 60vac at the outlets, rotor ok avr bad, A good visual inspection of generator head wiring should find that loose brush holder , without all the resistance reading's, Which could have been done after fixing the loose brush

Anything in the old Honda "G" series is bulletproof. Poor materials. Examine the brush holders for wear as they look a cheap soft plastic.

Page 18:43. The second example prompted me that both faults could not have happen had the slip rings began perfectly free of varnish. If rings had vanish coating (by accident or carelessness) test run could break up some coating but all, speculating that the factory no load test return with an OK status. Operating it in the field with substantial load, when encountering vanish interruption there was an electric arc and arc heating, when the interruption suddenly subsided the AVR surge current into the field coil and generate I^2*R heat.

11:47 - Where did the Freaking Magic New Brusholder come from???? The one I saw removed was toast?