• If you like what you see here and your interests are compatible with our 30,000 other users, Welcome. Fill out the registration form with your interests, your real name (seen only by moderators) and your city, state or country. Be certain that you have spelled your email address correctly! Your account is then manually checked and approved.

1951 Kohler 350M21 350 Watt Generator Set #154768

turtmaster

Subscriber
Last Subscription Date
07/01/2020
Re: 1951 Kohler 350M21 350 watt generator set #154768

after cleaning the crank case out with gas, id probably run rotella 15-w40 in it, along with a bit of MMO (marvel mystery oil) to help clean it out, along with a bit of running the engine with a few short oci's.

very cute little gen, wish i had one, good luck.
 

Vanman

Subscriber
Last Subscription Date
06/10/2020
Re: 1951 Kohler 350M21 350 watt generator set #154768

So, because I just LOVE to experiment, I am currently running my WHOLE house on this little Kohler. It's running this computer, which is playing music, as well as a couple of lamps and the telco equipment.

When I first switched off the main, the meter was showing a 30 watt load (mainly just the telco equipment), but when I threw the load on the generator, evidently the refrigerator wanted to defrost. It worked, almost full load though.

When it came time to start the compressor- the main experiment- that was a no go. The engine didn't lug, the generator just doesn't have the electromagnetic cajones. Too bad. My 800 watt Kohler, driven by a B&S Model B, starts up the 8 kbtu/hr window A/C as though it was on the mains. Then again, you don't just pick up that set with one hand lol.

Here are a couple of blurry photos of the metering equipment in the hall. Need to figure out how the governor is adjusted on this engine. Frequency was around 58 cycles, no load, 54 - 55 on load.

Keith
 

Attachments

Motormowers

Subscriber
Age
55
Last Subscription Date
07/13/2019
Re: 1951 Kohler 350M21 350 watt generator set #154768

I would love to find one of these for myself
 

Vanman

Subscriber
Last Subscription Date
06/10/2020
Re: 1951 Kohler 350M21 350 watt generator set #154768

There has been one on fleabay for a LONG time, for crazy money. $600! :crazy:

I would imagine that it is still there. If you're lucky enough, it may be close enough that you can drive over to it and strike up a somewhat reasonable deal, in person.

I'll see if I can find it again.

Well, evidently it's gone, even from the completed listings. I hadn't been "watching" it, so I don't know if it sold, or he gave up.

Here's a 1000 watt Kohler Automatic. Doesn't have the cuteness factor though.
http://www.ebay.com/itm/162566338733

And here's one that I *really* want. An 800 watt Kohler Automatic. This is powered by a Briggs Model B. Again, at ~250 lbs, is lacking the cuteness factor. :)
http://www.ebay.com/itm/253037375543

Keith
 
Last edited:

Vanman

Subscriber
Last Subscription Date
06/10/2020
Re: 1951 Kohler 350M21 350 watt generator set #154768

Since I had left ~1/3 of a tank of fuel in this set after I ran it last time, in May, I decided that I needed to use it up, before it went bad.

It ran right about one hour on that little bit of fuel, the longest I have run it yet. And I'll tell you what *everything* on this thing gets HOT when run for an extended period!

I used it to run a fan and some lights in the bedroom, and charge my phone. Later I ran my computer monitor, speakers, and desk lamp with it.

But I also performed another experiment- starting and running a 1/4 hp motor on it! It's quite amusing, but also illustrates just what is possible, when the conditions are right, in this case no load on the motor. Full load current for the motor is 5 amperes, and full load current for the generator is 3 amperes, so it's really quite remarkable to be able to get it started.

https://youtu.be/8HgkZA1wwB0

Here's an old film of the motor itself, including what it sounds like when started across the line- comes up to speed a wee bit faster. :D

https://www.youtube.com/watch?v=yjeq8ddBeyY
 

sbbloom69

Registered
Re: 1951 Kohler 350M21 350 watt generator set #154768

I know this is a year-old post, but I just noticed that you resurrected a Kohler 350M21 genset. I have three of them. All of mine came from a defunct Civil Defense fallout shelter. They all have the same Kohler K7 3.5/4.0hp engine and a 110VAC 350 watt "alternator". I actually found a real manual for this set, except that the carburetors on mine are Carter v.s. Tillotson. You may have figured out that the governor control is "backwards" compared to a similar BS. These little gensets are fixed with voltage regulation. Nominally, it's 110V at 60hz. So far, the best I've response I've gotten is 121V and 62 hz unloaded, and 59hz and 109V fully loaded. Good enough for 1951 lights and emergency radios. I'm going to try and find the manual and scan it to the site (I may have already). If you search for Kohler 350M21 you will find my posts from 2014.
Stuart
Los Alamos, NM
 

Attachments

Vanman

Subscriber
Last Subscription Date
06/10/2020
Re: 1951 Kohler 350M21 350 watt generator set #154768

Hi Stuart, nice collection! :wave:

Keith
 

s100

Registered
Vanman,

If those little engines are like the bigger ones (I think K11) then there is an adjusting screw with a lock nut somewhere on the carburetor side of the engine to adjust the governor. It's been years since I looked at mine but that is what I recall. I can't tell you if turning IN or OUT makes the engine run faster but it's easy enough to find out. I used the K11 a couple of times during two of our numerous power outrages and at I think 850 W it ran the fridge and the deep freeze quite well, and simultaneously although I don't think I would want to load it much more. That said it chugged happily (and economically) away for hours at a time. Since mine had the automatic load sensing start/stop feature I suppose I could have set it up and walked away but I never tried that. The carburetor (Carter N) was badly worn and finally the engine flooded and gave up the ghost (temporarily). I put it away and while I have carburetor kits now for the N's I just have not gotten back to it.

sbbloom69, those engines are not 3.5/4.0HP. They are 3/4HP. They are only 1800 rpm and no one would use even a 3HP engine on a 300W machine. Since 746W = 1 HP then 300 watts is just about right for a 3/4HP engine.

I kick myself regularly when I see people posting cool stuff here, because at one time or another in the past I did not avail myself of opportunities to buy similar things. These little gensets are a good example. A few years ago someone had one on craigslist for I think $40. It looked nice and was complete but the ad said the tank was full of crud and syrup. But it was winter and it was cold outside, the genset was probably 20 miles away, the seller got my nose out of joint when he said someone could use it for a "mini bike motor" and he would not take my top offer of $25. For $40 I could have had the set but I chose not to bite. Given the same opportunity today I would probably spring for the $40, mini bike insanity or not. But then I have lots of junk already, and nearly all of it is clamoring for some sort of attention.

When can we expect to see the opening of "Van Man's Prehistoric Light Plant Museum?" Might almost be worth the drive or better yet AMTRAK from Detroit!
 

Vanman

Subscriber
Last Subscription Date
06/10/2020
As it happens, I have a need for this little set, so I've been working on it a bit.

When I got it, it's air cleaner was improperly installed and broken. In the meantime I bought another air cleaner, but it didn't have the right "look". Much more recently I bought a little air cleaner for my Briggs WM.

I got to looking at all of the air cleaners and hatched a plan to use the upper part from the Kohler and the lower part from the Briggs.

It required some adaptation but no modification, so I can still use the Briggs air cleaner on the Briggs. The inner tubes were different sizes, so the copper tube serves as a sleeve to make up the difference. The bottom of the Briggs cup is supported and sealed with a fender washer and a neoprene washer. I even got a fiber washer to go under the wing nut. :D
 

Attachments

Last edited:

Vanman

Subscriber
Last Subscription Date
06/10/2020
I was thinking that the generator looked a little dirty inside, so I thought I probably ought to pull it apart and clean it out before running for any extended period. Good thing I did! :crazy:

Will get after it with some compressed air a little later on today. :brows:
 

Attachments

Vanman

Subscriber
Last Subscription Date
06/10/2020
There, that's better. Not "perfectly" clean, but perfectly serviceable. I'm putting a light film of oil between the iron and aluminum parts. Hopefully that will help prevent the rust and corrosion I encountered. A little grease probably would have been better, but the oil was handy.

I had given the armature through bolt a few good whacks to see if it wanted to come off, but it wasn't interested. No problem, I just cleaned around it.

The generator bearing is just *slightly* rough, so I guess I really should replace it. The end bell was pretty tight when pulling it off, so that probably damaged the bearing.

Looks to be 1-3/8" OD, 9/16" ID, and 1/2" wide. Any brand and source recommendations? I'll pull it and measure it carefully before ordering.

Keith
 

Attachments

Last edited:

Newoldstock

Registered
Looks to be 1-3/8" OD, 9/16" ID, and 1/2" wide. Any brand and source recommendations? I'll pull it and measure it carefully before ordering.

Keith
I never went wrong with a FAG or SKF. ( most bearings sold seem to be these two brands )
Nachi are good too but I have had some so hard that I chipped the inner racing tapping on the shaft.

Its probably sitting on a shelf in town no need to order.
I am told some people here are having trouble sourcing bearings.
I never did I got them from one of several small local shops that supply local business.
You might also find what you need in an electric motor rewind shop ( most sit on a consignment and pay as they go using the stock )

Where practical on Generators use a 2RS bearing ( even if it did not come that ) because the seals will prevent dust and dirt and keep grease in place.
Make sure they sell you a C3 clearance bearing ( this has .003 room for the balls to spin at high speed and with slight misalignment )

Because of the age you should mic the journal of the shaft and housing for the outer race.
The bearing supplier in your area can tell you the tolerances you need for your bearing ( your going to be in the .0005 range in many cases )
Never use locktite, never hammer on them in a way that will put a shock on the balls and races.
Most of the time these things will slowly rotate in a housing to ensure proper wear but be an interference fit on the shaft.
You can heat a bearing in the oven to around 200 F to help slide it on shaft or freeze the shaft or both.

Avoid hitting, pressing anything because the act of tapping a bearing on a shaft can sometimes shift the armature and screw things right up on you.
 

Vanman

Subscriber
Last Subscription Date
06/10/2020
I just came in from the shop (laundry room lol) after pulling the bearing and measuring. It was pretty tight on the shaft.

The shaft measures 0.551". This works out to 14mm, which appears to be an odd size.

This is an oddly wide bearing, though the width is non-critical in this instance.

The inner race measures 0.566" wide. That's closer to 9/16" than anything else, but the width really doesn't matter, within reason. The outer race is narrower, though there's plenty of room for it to be wider, so I didn't even measure that.

The outside diameter measures 1.377". Within spitting distance of 35mm. This was also a tight fit in the end bell, so I'd guess that an actual 1-3/8" OD bearing would work.

Double sealed is my preference, but it is proving difficult to find anything in that size.

I'm familiar with the bearing handling protocols, and it made me cringe to have to pull so hard first the end bell, then the bearing itself to remove it. I know they don't like that. :(

I doubt there are any bearing houses or motor shops around here. But I'll check. I normally just mail order stuff. I can't stress enough what it's like here lol.
 

Newoldstock

Registered
Most bearings are in metric these days, and going back a long time too.
I am hard pressed to remember the last time one I dealt with was not.

Odds are someone has bearings.
Ask at the nearest machine shop or repair centre for machinery that might use bearings if they can point you in the right direction.

My local autoparts supplier is my nearest bearing source.
They have all the common stuff you would use to repair wheels on the kids mini bike or idler wheels on the snow machine skid ect..

What they don't have they order.

Measure in two places on the housing.
Motor/generator end bells tend to wear egg shaped.
After a while you get really good at feeling the tolerances of the bearing and parts and you can tell right away if things are too tight or loose or something is just wrong.

I have a little Johnson 300 watt unit not all that different I have pull out and work on one of these days.
 

Vanman

Subscriber
Last Subscription Date
06/10/2020
Man, that 14mm bore really seems to be an odd duck! Grainger and McMaster Carr skip right over that size.

But here's a listing for the exact bearing. Mine looks JUST like these, and measures the same. Maybe I can now cross reference that part number. :D I would really like to find the same thing in double sealed instead of just shielded. :brows:

I can drop by the auto parts store, but even those aren't very good here. There is no Napa, for instance.

https://www.ebay.com/itm/4-NIB-NDH-...473215?hash=item465303de7f:g:vOkAAOSwdzVXriMI
 

Newoldstock

Registered
Maybe there is a Jacuzzi, Xyleme or Armstrong pump dealer you can visit?

45 bucks for 4 when all you need is one.
And it does seem kind of expensive.

Small bearings like this are really cheap should not cost more the 2 or 3 dollars

Wajax!
might be a dealer nearby try them their big and everywhere.
 

Vanman

Subscriber
Last Subscription Date
06/10/2020
Well, right or wrong, for better or for worse, I ordered this, $13, delivered:

https://www.ebay.com/itm/201990942152

I dug around on the net trying to find local places to go, and just came up dry. No pump distributors or bearing suppliers. I even found the site for the bearing supplier for the FLAPS, and they do not list that bearing on their site.

I too am used to bearings like this only costing a few bucks, but the only new ones I could find were all well over twenty, and not really an identical match in terms of the inner race being as wide as the original.

Since it's shielded instead of sealed, I will put a wee bit of grease around the gap and call it good.

There is a part of me that likes the fact that an old, new old stock :D, made in USA bearing, of original design, will be going in. I'm sure it'll do just fine. :)
 

Newoldstock

Registered
They made bearings in the USA?
I though they all came from Germany and Japan ha ha.

I just thought of something.
Delco...
Maybe its the same bearing GM used on alternators?
From a rebuild kit perhaps?

Sometimes you have a hollow inside the end bell.
You would fill this with grease and over time the bearing ( even with shields ) will pull a little grease in if it needs it.
Trouble is too much grease is bad, wrong grease is bad.
Unless you have a cavity made with a grease fitting and purge port I would not bother.
You don't want to contaminate the inside of the machine.
 

Vanman

Subscriber
Last Subscription Date
06/10/2020
The bearing bore in the end bell on this one is open, being covered only by the sheet metal brush cover when it's installed.

Delco,... Some automotive generator or other came to my mind too... :shrug:
 

Vanman

Subscriber
Last Subscription Date
06/10/2020
Well, I decided that, even though the engine ran great last time, I should check the ignition and valve lash. Seeing how filthy it was inside the generator, it's no surprise at how it looks behind the blower housing.

The coil tests good, I assume. 4k ohms seems reasonable. It was working. I put a zip tie around the rubber high tension bushing to avoid breaking the wire while the coil is out of the housing.

Points seem good, they looked a little tight on the gap, so maybe it'll run even better when they're adjusted to spec.

Condenser measures in megohms, but never reaches infinite, even with a multimeter, so will put in a new one. Didn't check with the condenser tester as that requires me to borrow a rectifier tube from my radio, and that's backed up against a wall.
 

Attachments


Top