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1951 Kohler 350M21 350 Watt Generator Set #154768


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  #41  
Old 09-27-2018, 09:55:30 PM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

The bearing came in, so got the end bell / brush rigging and brushes reinstalled and hooked up. I left the generator cover off so I can observe the brushes for sparking. There's a bit of movement available in the field frame and end bell, so I should be able to move them around for best commutation.
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Old 10-01-2018, 12:18:34 AM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

I cleaned up the engine as best as I could. Neither Gunk nor Super X engine degreasers are really very good, but it's a lot better than it was.

I pulled the valve cover and found the clearance to be 0.013" intake, 0.015" exhaust. They're supposed to be 0.004". And now they are. I checked them at every quarter turn of the crank. The intake ends up being 0.005" at TDC compression.

And a big plus- the cover came off and left the gasket entirely intact! Yay! That sort of win is rare for me lol.
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Old 10-01-2018, 04:12:10 AM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

Got the rocker cover and crankcase vent back on. I hate bolt holes that are open to oil or water on the other end, so I used a wee bit of pipe dope on their threads.

Engine is a lot cleaner than when I started, but up around the exhaust valve and cylinder area, it's just covered with baked on grime.

Any recommendation for a brand of carb cleaner or something that actually works?
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  #44  
Old 10-01-2018, 05:53:29 AM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

I use "Gum Cutter" for small parts and those hard to reach areas like you have pictured.
https://www.berkebileoil.com/instant-gum-cutter.html
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  #45  
Old 10-03-2018, 01:26:11 PM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

Got the magneto cleaned up, reinstalled, points adjusted, felt oiled, and have spark, but want to get a new condenser.

Also need to get a new plug as the wire has a ring terminal, and the tip of this plug does not unscrew.

Manual talks about setting the timing, but it's a little earlier ('49 vs '51), and this one does not appear to be adjustable, other than a tiny bit of play in the bolt holes. I biased towards advanced and called it good.

The FLAPS didn't have the Berkebile cleaner, will have to order some. In the meantime, I bought a can of Berryman's, and it cleaned up adequately enough for now.

Keith
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  #46  
Old 10-04-2018, 06:57:47 PM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

And we have life! Right there on top of the washing machine!

After getting the new condenser, flywheel, blower housing, starter pulley, and new spark plug installed, I gave her a big snort of ether down the throat (too much, as it happens). After a few good pulls, away she went, and so did the 300 watt bulb I had plugged in.

I had cleaned most of the grime off of and out of the blower housing, but stopped when it cut my thumb. Good enough.

After today's sucessful test, I made a gasket for the air cleaner to carburetor inlet. Next to install the air cleaner, some fuel, and take her outside for a good test.

I still want to get a spring to take up the throttle linkage slack too.
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  #47  
Old 10-04-2018, 11:34:09 PM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

Man, what a sweet little runner! Just sounds about like an idling lawn mower.

Had to lean out the mixture a bit now that I'm running with a proper air cleaner. Adjusted the throttle linkage, then the governor.

Before the generator warmed up, I got 60 cycles and 120 volts with a ~265 watt load (300 watt, 130 volt bulb). No load was around 126. My meter doesn't like to read frequency from unloaded collector rings. A small bulb probably would have fixed that. But the governor is now very responsive, stable, and repeatable. What a nice machine.

When the generator was hot, I was showing about 116 volts with the same bulb, still right around 60 cycles, and just over 120 no load.

Seems to be smoking a fair amount, grey oil burning smoke. I'll try switching from 5W-30 to SAE 30. The breather vents into the cooling air stream under the blower housing (gee, I wonder why it was so grimey under there!?! ).

But starts right up, doesn't even need a crazy pull on the rope. Just ger 'er rolling over and away she goes. Going to be a great camping generator if my inverter will synchronize to it. I'm going to test that on Saturday.

I filled the 1/2 gallon tank, and was going to let it run it all out, but after an hour so, the level only went down an inch or so from the top of the cylindrical tank!
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  #48  
Old 10-07-2018, 01:59:45 PM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

Well the spring for the throttle linkage didn't work. Even though it was a very light spring, it increased the governor droop quite a bit. No big deal as the linkage doesn't really jiggle around too much without it. It was an interesting experiment.

Yesterday I took the little guy up to the high desert where my bus and Trace inverter are kept. Ran some tests, made some adjustments, and was ultimately able to achieve satisfactory operation with the two in parallel. So this is a win.
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  #49  
Old 10-07-2018, 04:24:16 PM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

It is interesting to note that, when the AC input amp limit (on the Trace inverter) was set to 3 amperes, the voltage fell too low (I had the lower limit set at 100 volts), and it would trip off line. Set to 2 amperes it worked great. I will have to check with an actual ammeter, but I suspect the inverter's amp sensing is not all that accurate and it was taking more than 3 amperes.

Also interesting is that the inverter passes on the load power factor through to the generator. This was a bit of a surprise as it would have been so easy for them to design it not to do that.

So, even set to a 2 amp input limit, with the generator happily puttering away, a mercury vapor lamp applied to the inverter output would cause the generator voltage to drop below the 100 volt limit I had set, and it would of course trip off line.

One thing I have never liked about this inverter is that it will not curtail the load on it's source in order to keep the voltage above the value selected. It'll just keep loading it up to the amp limit you set, trip off, synchronize, reconnect, load down, trip, repeat...

Too bad Trace is gone, as I'm sure these could easily be fixed in software.

Interestingly, this little generator is very feeble with lagging power factor or overload. Without the inverter, it would not even start my little mini fridge. Of course, paralleled with the inverter it was no problem as it is a 4kW inverter, rated to surge up to 10kW.
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Old 10-07-2018, 09:43:03 PM
Zephyr7 Zephyr7 is offline
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

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Originally Posted by Vanman View Post
Also interesting is that the inverter passes on the load power factor through to the generator. This was a bit of a surprise as it would have been so easy for them to design it not to do that.
Actually, and unfortunately, it’s not so easy. It’s easy to filter out the high frequency switching from the inverter (a small LC, inductor capacitor, network). Unfortunately, it takes a LOT more to filter out the 60 Hz ripple that comes from the inverter. You need much more inductance and capacitance to do that. Power factor comes down to misaligned current and voltage waveforms on the AC output so that gets through too. The inverter would be a lot larger and heavier if it had the necessary filtering.

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So, even set to a 2 amp input limit, with the generator happily puttering away, a mercury vapor lamp applied to the inverter output would cause the generator voltage to drop below the 100 volt limit I had set, and it would of course trip off line.
This is probably due to the very poor power factor presented by the magnetic ballast I assume you’re using with the mercury vapor lamp. The MV lamp is an arc light, so it presents an impulse load and the ballast only filters that a little. The inverter sees the load as a series of relatively high-current pulses and not a nice sine wave. If you can get an electronic ballast that will probably help since those are generally power factor corrected to better than 0.9.

Quote:
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Too bad Trace is gone, as I'm sure these could easily be fixed in software.
It would need hardware to fix. They could probably only change some of the shutdown parameters and maybe current limit settings in software.

There is some hope though. Get a big (several hundred thousand microfarads) “computer grade” capacitor. Wire it in parallel with DC bus for the inverter. That capacitor will help with the transients and 60Hz ripple. You want something with a higher voltage rating than your charging voltage. 35v minimum for a 24v system, and higher would be safer.

Bill
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Old 10-08-2018, 01:02:23 AM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

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Originally Posted by Zephyr7 View Post

There is some hope though. Get a big (several hundred thousand microfarads) “computer grade” capacitor. Wire it in parallel with DC bus for the inverter. That capacitor will help with the transients and 60Hz ripple. You want something with a higher voltage rating than your charging voltage. 35v minimum for a 24v system, and higher would be safer.

Bill
That is a lot of stored energy. Probably should include some circuit protection in case something fails.
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Old 10-08-2018, 11:05:30 AM
Zephyr7 Zephyr7 is offline
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

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That is a lot of stored energy. Probably should include some circuit protection in case something fails.
Usually the caps don’t have any protection of their own, they’re just circuit elements. It wouldn’t hurt to add a beefy breaker though.

Bill
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Old 10-08-2018, 12:16:39 PM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

Bill, they usually don't, but several hundred thousand microfarads, even at 24 volts is a lot. Suspect enough energy to vaporize traces on board, probably most components on board.

Not one I would discharge by shorting out with a screwdriver.
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  #54  
Old 10-08-2018, 05:39:44 PM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

The inverter manual discusses running the DC cables adjacent to decrease their reactance, thereby reducing the load on the internal caps that are on the DC bus. Indeed this gave me the idea of putting a big 40 volt cap across the DC terminals as well.

This inverter operates in paralell with the AC source, and controls the magnetude and direction of power flow between the DC and AC side by adjusting the ratio of transformation between the two.

It is also capable of handling down to a 0% power factor in either direction.

These are the reasons that it could be programmed to correct load power factor as seen by the AC line.

As for heft, it's a beast at ~120 lbs.
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Old 02-02-2019, 11:48:39 PM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

Here's an update on this little Kohler. The trip I had planned on using it on ended up not coming to fruition. Story of my life. Hopefully this will change soon. Anyone want to buy a house?

So, it had been sitting with maybe 1/3 of a tank of gasoline for four months, and, of course, these little tanks are not air tight. Of course they have to vent.

So I finally decided that this evening I would see if she'll still light off, and spend the fuel lighting one or both of the two lights that burn in my back yard every night anyway. One 175 watt Mercury Vapor and one 70 watt High Pressure Sodium. Yeah, I'm a lighting nut too.

It took three or four pulls and some choke finagling but she sounded as good as ever after that. Fuel was probably getting a little old, losing some of the more volatile compounds already.

Plugged in the Merc, no problem! Sweet, lets add on the Sodium. Awesome! She runs 'em both. Check the line amperes since those ballasts are quite reactive, but the current wan't bad, just over three amperes.

Interestingly the flickering due to the 15 power strokes per second was quite visible in the Merc, and not visible at all in the Sodium.

It was amazing how long it ran on such a small amount of fuel. At least two hours. Finally got it all used up, and have removed the fuel cap to let the tank dry out. I was able to make it out there in time to add some choke to help get some more of the last of the fuel out of the carb.
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Old 02-26-2019, 08:38:42 PM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

I do not jump on board with everything new. I generally avoid new whenever possible. In almost every case, old is better. Tools are no exception. Here's my answer to battery tools.

I had to saw up a cheap, ratty ladder so it would fit it in the garbage. It was fun!

Next I think I'll use the angle grinder with wire wheel to work on the other Kohler project!

Keith
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Old 02-27-2019, 11:34:26 AM
Zephyr7 Zephyr7 is offline
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

Vanman, some of the cordless tools these days are really awesome. There are even good cordless hammer drills (I didn’t believe that until I actually tried one). The Milwaukee and Bosch stuff is really good but expensive. The ryobi stuff at Home Depot is actually quite good, and cheap too. I’ve been really happy with the stuff I have.

I still prefer my Bosch sds+ rotary hammer drill though for heavy duty drilling in masonry.

I think the key to getting good tools isn’t so much to get old stuff as to not get “consumer” junk. The pro stuff is still made to high quality levels, it just costs more than most home people are willing to pay.

Bill
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Old 02-27-2019, 02:39:14 PM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

I know, some new stuff is actually pretty well made, and sometimes technology has given it "a leg up", despite more plastic instead of metal, etc. And I get the advantages. Lighter weight, so easier to handle, no cords, etc.

But I like to demonstrate that old stuff also gets the job done, just as it always has.

The reciprocating saw isn't actually old, I bought it new in the '90's. But it is heavy duty, and it's battery never goes dead or needs replacement. I've used and abused it on all sorts of projects, yet I have never had to fix or replace anything but blades.

I think the little 350 watt genny qualifies as "old", being from 1951, but it works fantastically well, and is so pleasant puttering along at 1800 rpm. It has zero electronics waiting to fail, and practically zero plastic waiting to break. I'd like to get one of those nice old cast aluminum Sawzalls from that era to go with it.

Keith
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Old 02-27-2019, 04:04:21 PM
Zephyr7 Zephyr7 is offline
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

A good example of tool technology and upgrades is the original skilsaw, the worm drive one. All they’ve done over the years is make it better. The most recent one that I have is made mostly of magnesium so it’s lots lighter weight. The only downside is the magnesium is more likely to crack than bend if you drop it, but that’s just a property of the material. The weight savings really does make the saw a lot easier to handle, I really like it.

Black and decker is an example of stuff getting made cheaper over the years and not better. Craftsman power tools are another example. I wasn’t happy when the craftsman hand tools started being made in Taiwan, either, but at least the quality of those seems to still be pretty good.

Bill

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Old 02-27-2019, 04:14:49 PM
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Default Re: 1951 Kohler 350M21 350 Watt Generator Set #154768

Ah, yes, I can identify with the good old worm drive Skilsaw! I have a neat, OLD 8-1/4" job, and it is indeed a BEAST! Needs a shaft seal though. Likes to mark it's territory lol.

The little Kohler is not going to run this guy.

Keith
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