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Kohler Military 1500watt 1.5kva 1M21H

KidDynamo

Subscriber
Last Subscription Date
02/18/2020
This Kohler is the familiar old design but in military configuration with a complete housing enclosure and gas tank.

To show you how far out into left field I sometimes wander, 3 or 4 years ago, I bought a WWII vintage, original Kohler spare parts crate, complete, for one of these 1M21H manual start generator units and then waited to find one of the generator sets close enough to me to go pick up!

I lucked out on this one, in some respects. Of course I obligated myself to buy it and then went and looked at it. (LOL) When I opened the radiator cap, it was full of 50/50 and wasn't leaking. The oil was decent looking and the gas was old but not rotten. Still, I removed the housing assembly top, with the gas tank attached, and cleaned the tank a bit.

The gas line had an in-line strainer with clear glass bowl and an integral shut off but it was missing the ceramic element. I had found one two days earlier., (!?!), so I popped it in and then removed and cleaned the carb.

Next, the magneto and valve cover were removed. The magneto points were cleaned and the mag was hot, hot, hot, so I re-installed it, setting the coupling halves back as marked before removal. I consulted the manual pages that I had photocopied and eye-balled the rocker arms to check timing to be good, as per the book.

Before I was done, I had removed and re-installed the mag about a half dozen times because it would lose spark quickly (10 to 30 seconds). Problem was eliminated by wiring brushing the entire points, in situ, stropping the points with a piece of 220 garnet paper, and then stropping them with a pristine clean piece of paper.

At this point, the unit would crank up and run great, but with a full load, the thing would eventually quit running. A check of the mag showed it was awesome. What !?! The carb bowl wasn't feeding well and a quickie re-cleaning of the needle, seat, float, and pin wasn't enough so I swapped out the carb top cover, float and valve assembly with that from another carb I had, resulting in a total cure. (I'll fix the original later).

Those of you who have one of these old Kohler's know how cool they sound, loping along at 1200 rpm for the 60 cycle units and similar slow speeed for the d.c. units! This thing cranks up easy as pie and seemed to sip the fuel. I didn't do any close measuring but three hours of steady 1500 watt heater load and intermitent 2300 watt overload used so little I couldn't tell. I'll have to do a better test run soon.

My unit was built in 1945, has the typical Vee-belt fan, Bosch mag, and aluminum carb of that era. Note that the valve cover has wing nuts for hold down, a pipe plug in the usual filler hole and a filler pipe and cap fitted into the side to accomodate the housing enclosure. No fuel pump is fitted as gravity feed is employed. The choker assembly is manual only with no provision for a choker coil, just a cover plate on the choker housing.

The carb design still retains the overflow port from the vacuum fuel pump days and although it is merely plugged, removal of the plug allows for convenient checking of the carb fuel level and float valve performance. (I can attest to this, personally!)

Anyway, I really like these units! I've long thought that when the original first appeared about 1920 in the form of a Kohler D, I believe, they were quite modern but technology moved quickly and far yet Kohler was still milking that once modern design long after the fact. Take for example the Onan military W3-C plant was similar but had half the cylinders, similar overall size, but twice the output!

Having said that, with proper maintenance, I suspect these Kohler units might run a long, long, time. I live in the city and rarely lose power for more than a flicker, but I'm ready! Some of the city folks ask about the Kohler's output and I say: "1500 watts" and some go o-o-o-o-h, like it a lot. Then I tell them it is the same as one electric heater and that's when the head-scratching starts! :crazy: LOL !!

(Did I mention that I've had an original WWII military spare parts crate for a W3-C for a couple years now, too? I wonder what's next?) LOL
 

Attachments

K D Redd

In Memory Of
I know LITTLE about your unit BUT I would think if your generator was a military unit it would have the sheilded ignition wires and spark plugs with thread on the top of the plug where the plug wire SCREWED on. I have a B&S engine Model ZZP from May of 1942 that had the remnats of a sheided plug wire when I bought it at an auction.

Kent
 

KidDynamo

Subscriber
Last Subscription Date
02/18/2020
..........I would think if your generator was a military unit it would have the sheilded ignition wires and spark plugs with thread on the top of the plug where the plug wire SCREWED on..........

Kent
Good observation ! I thought about that too but maybe I've allowed the olive drab paint color to cloud my thinking. I have maybe 6 or 8 gensets that are for sure military tagged and they all have shielded ignition wiring.

So far, I have not found any military i.d. tags (or empty rivet holes) although I have one more item to check.

This magneto and cap have matching paint to the engine so one might reasonably conclude that they are original to the unit.

I'll be doing a bit more checking. Thanks for your interest and ideas!

If anybody else has one of these, and particularly if it is military, Id sure like to see photos.
 

Jim Rankin

Registered
Age
58
Cute little thing isn't it!

Anyone know how the vacuum fuel pump thing worked? I have an old Caterpillar with the extra carburetor connection on the side of the bowl.
 

Andrew Mackey

Moderator
Last Subscription Date
05/14/2017
The 1 M 21 M is a manual start unit, the 1 A 21, an automatic. Both use the same engine, and the generator sections are nearly identical as well, the main difference being the auto start box. As for the engines themselves - the main design goes back to the A series, started in the mid teens! I have a C model, DC, from 1920, and internally, the engine was nearly exactly the same as a 1947 1 M 21, I also had. The main differences: aluminum rocker supports, instead of the pot metal on the C, heavier, and differently designed pushrods and rockers (I M 21 designed to last longer) 1 M 21 had 3 compression rings, and an oil ring, the C 4 compression rings only (it doesn't use any oil anyhow), and the 1 M 21 runs at 1800 RPM and is rated around 5 HP, as the C was rated at 4.5@1200. Part of the RPM change was reflected in the change to AC, from DC power. My C can do a lot more than 1800 RPM though! The pin came out of the governor arm one day, and the engine ran up in speed quite rapidly. I bet she was turning about 4 grand when all the bulbs I had on line suddenly blew their filiments, and that killed the power selenoid in the auto start, thus stopping the engine! :eek:
Andrew:D
 

Jeff Sabo

Registered
I thought I was the only person with one of these inclosed units. Very nice KID DYNAMO! Yes your mag is correct! mine is identical. I believe the metal enclosure cancels out the ignition noise.These carbys do not like gravity feeding. I have five other of these gennys all with fuel pumps, and I have had no luck gravity feeding, but run perfectly with fuel pumps. Mine is missing the sides, thanks for the pics.I should be able to reproduce some for mine now!
 

ListerDiesel

In Memory Of
Age
74
Last Subscription Date
10/24/2016
Look out for military manual # TM5-5371

This is the Army book for the 1M21 and 1A21 (which we have an as-new copy of)

When the round-tuits are sufficiently available we will get this scanned and onto our website. Some pages are already up there.

The book does not mention a vacuum portion of the fuel pump, only the manual operation by the lever, and it also covers the gaseous fuel model.

Peter
 
D

Don Smith

Guest
I just got a Kohler 1E21-? (cannot read the last digit) It is a military unit with autostart and 32 volt dc/120ac. Runs great. Just have to get the autostart operational The military tag is on the generator housing just to the right of the engine tag. More info on my unit on other posting. Pictures to follow. Don Smith
 

fordiesel69

Registered
Why, do you have one for sale?

I hear the manual and auto models really do not change in value much. They peak at $500 for a running but needs minor repair. Most will run but many will not produce electricity.

I got mine for practically free but it will never run, and will never generate. Too far gone......

I want to find one close to PA to buy.
 

Ed Stoller

Subscriber
Age
79
Last Subscription Date
07/11/2019
I notice the tag says 1200 RPM and 60 cycle. I was extecting either a four pole unit and 1800 RPM or a two pole unit and 3600 RPM. Is the generator belt or gear driven?

I have an Onan W3-C waiting for me to clean a place in the shop. Anybody know what the Army manual is for it?

I also have a dog house like that with no generator in it but a two cylinder Herc in it. Anybody have an idea what that might be?
 

G Sams

Registered
The AC models have a 6 pole generator and are direct drive. The generator turns at 1200 rpm. The DC models have 4 poles and are also direct drive but turn at 1000 rpm.
 

Andrew Mackey

Moderator
Last Subscription Date
05/14/2017
With the DC Kohler letter series, RPM rating changed with the watts listed. The basic engine design did not change, compression ratio and RPM changes were made to increase power. I have heard that Kohler got as much as 20 HP out of the engine - experimentally, but reliability suffered greatly at the high power. The crank only has 2 mains, one at each end! The 1A-21 (1947) I use for stand-by power uses about 1 gallon of fuel for 4 hours, under heavy load. Under light load, 1 gallon in 8 hours! (100 watt load):cool: Similarly, my 1920 'C' model Kohler (110VDC) will go about 6 hours on a gallon of gas, under 1,000 watts of load at a show.
Andrew:D
 

EdwardLowell

Registered
Last Subscription Date
12/31/2015
hi k d. not sure im doing this right ??? ive got the same unit here. dont remember if the mag is the same. ill look tomorrow. it runs as good as new. mine dosent have the gas tank but it has a fuel pump and i guess it had a remote gas tank ??. have several other military gen sets and as you say most of them do have shielded ignition. i do think however that this unit didnt. they sure run smooth. weve also got the first model kohler with the stewart warner vacuum fuel system...it is 110 volts d.c. hope i did this right.......ed lowell
 

StillKickin

Subscriber
Last Subscription Date
02/24/2020
This Kohler is the familiar old design but in military configuration with a complete housing enclosure and gas tank.

To show you how far out into left field I sometimes wander, 3 or 4 years ago, I bought a WWII vintage, original Kohler spare parts crate, complete, for one of these 1M21H manual start generator units and then waited to find one of the generator sets close enough to me to go pick up!

I lucked out on this one, in some respects. Of course I obligated myself to buy it and then went and looked at it. (LOL) When I opened the radiator cap, it was full of 50/50 and wasn't leaking. The oil was decent looking and the gas was old but not rotten. Still, I removed the housing assembly top, with the gas tank attached, and cleaned the tank a bit.

The gas line had an in-line strainer with clear glass bowl and an integral shut off but it was missing the ceramic element. I had found one two days earlier., (!?!), so I popped it in and then removed and cleaned the carb.

Next, the magneto and valve cover were removed. The magneto points were cleaned and the mag was hot, hot, hot, so I re-installed it, setting the coupling halves back as marked before removal. I consulted the manual pages that I had photocopied and eye-balled the rocker arms to check timing to be good, as per the book.

Before I was done, I had removed and re-installed the mag about a half dozen times because it would lose spark quickly (10 to 30 seconds). Problem was eliminated by wiring brushing the entire points, in situ, stropping the points with a piece of 220 garnet paper, and then stropping them with a pristine clean piece of paper.

At this point, the unit would crank up and run great, but with a full load, the thing would eventually quit running. A check of the mag showed it was awesome. What !?! The carb bowl wasn't feeding well and a quickie re-cleaning of the needle, seat, float, and pin wasn't enough so I swapped out the carb top cover, float and valve assembly with that from another carb I had, resulting in a total cure. (I'll fix the original later).

Those of you who have one of these old Kohler's know how cool they sound, loping along at 1200 rpm for the 60 cycle units and similar slow speeed for the d.c. units! This thing cranks up easy as pie and seemed to sip the fuel. I didn't do any close measuring but three hours of steady 1500 watt heater load and intermitent 2300 watt overload used so little I couldn't tell. I'll have to do a better test run soon.

My unit was built in 1945, has the typical Vee-belt fan, Bosch mag, and aluminum carb of that era. Note that the valve cover has wing nuts for hold down, a pipe plug in the usual filler hole and a filler pipe and cap fitted into the side to accomodate the housing enclosure. No fuel pump is fitted as gravity feed is employed. The choker assembly is manual only with no provision for a choker coil, just a cover plate on the choker housing.

The carb design still retains the overflow port from the vacuum fuel pump days and although it is merely plugged, removal of the plug allows for convenient checking of the carb fuel level and float valve performance. (I can attest to this, personally!)

Anyway, I really like these units! I've long thought that when the original first appeared about 1920 in the form of a Kohler D, I believe, they were quite modern but technology moved quickly and far yet Kohler was still milking that once modern design long after the fact. Take for example the Onan military W3-C plant was similar but had half the cylinders, similar overall size, but twice the output!

Having said that, with proper maintenance, I suspect these Kohler units might run a long, long, time. I live in the city and rarely lose power for more than a flicker, but I'm ready! Some of the city folks ask about the Kohler's output and I say: "1500 watts" and some go o-o-o-o-h, like it a lot. Then I tell them it is the same as one electric heater and that's when the head-scratching starts! :crazy: LOL !!

(Did I mention that I've had an original WWII military spare parts crate for a W3-C for a couple years now, too? I wonder what's next?) LOL
KidDynamo - I have a 1M21H looks exactly like yours in "Army2.jpg" except mine has been painted red.? Anyway I see that you have copied manual for the Dynamo. any chance I can get a copy of manual? thanks, Darrell
 

dkamp

eMail NOT Working
Wow... 2011 was 8 years ago...
but he might, because he's still around.

BTW... KD inquired about the lack of RF shielding... when THESE generating plants were used by the army, there was no significant radio activity occurring that would have been interfered-with. it wasn't until middle WW2 where RF shielding became a concern, and not until the 1950's where it was a priority.
 
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