Jewels of Stockton: Samson Juniors

By Staff
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The busy side of the Samson, showing belt drive to the governor/mixer assembly, rocker arm for exhaust valve, and igniter and trip mechanism. These were volume-governed engines, the governor acting directly on the mixer.
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Lester's 1- HP Samson Junior wears serial number N841 and likely dates from around 1904. The Samson Iron Works, Stockton, Calif., appears to have started operations around 1898. Production in Stockton continued until 1918, when General Motors bought the c
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Two valves plumbed into the mixer/vaporizer allow Lester to run the Samson on propane. Check out the igniter assembly - hard to believe it's not original. A good view of the flyball governor/mixer/vaporizer assembly.
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A good view of the flyball governor/mixer/vaporizer assembly.
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The flyball governor viewed from behind. You can just barely see the mechanism on the igniter pushrod that advances and retards ignition timing.

Samson Junior engines were the smallest engines built by Samson
Iron Works, Stockton, Calif. Rated at 1- HP, they were available in
either a pump jack or a belt model. The belt model is represented

The Samson Junior is a first generation design and was developed
by John M. Kroyer. Featuring a unique distillate vaporizer built
integrally with the governing mechanism, it is a tank-cooled engine
with low-tension igniter ignition.

I’ve admired these little Samson engines, with all their
wonderful bells and whistles, for many years, and some years ago a
friend of mine was very fortunate in acquiring the little Junior
you see here.

This particular engine came out of a pump house in Columbia,
Calif., which is in the heart of California’s gold country.
According to several people familiar with this particular engine,
it was complete and original until someone in the area stripped the
governor, igniter and pre-heater from it, leaving its
‘bones’ behind. From this point it went through several
hands until I received it through a trade. Thank you Chris
Tomasovitch, Columbia, Calif.

Chris had this little Junior for a number of years, all the
while searching for its missing parts but not having much luck. It
tugged at Chris’ heart every time he passed the little Junior,
stripped and naked as it was, so he went to work and manufactured
the necessary fittings and adapters to fit an old Ford Model T
carburetor to the Junior. He also fabricated an adapter plate for a
spark plug and a set of wipe contacts to provide ignition. Chris
was finally able to run the Samson, but found it would load up on
oil having quite a bit of blow by, but would run slowly just idling
along. He had made a runner out of it.

Chris knew I really wanted that little engine, and I finally
came up with something he wanted more than the Junior – it was
finally mine.

Engine collectors are the luckiest people. During the same time
period I was attending a swap meet when a good friend, John
Jarrett, came over and said, ‘The fellow over there has a
Samson governor, Les, and you better go look.’ I certainly did
go look, and sure enough there it was – a complete, early-style
governor/vaporizer assembly in solid bronze. Amazingly it was
tight, in almost new condition. I bought it, of course, but at the
time I wasn’t sure if it was for the 1- HP or 3 HP size Samson.
As luck would have, it fit the little Samson Junior.

The mixer was originally fitted with a preheater (presently
missing on Lester’s engine) running from the exhaust to the
bottom of the mixer. The hot air circulating around the mixer aided
in fuel vaporization, allowing the engine to run low-grade

I did, as it turned out, have to fit a -inch thick spacer
bushing between the timing gear and flywheel so the pulley groove
machined into the flywheel hub would align with the driven pulley
on the governor, but that was a small price to pay for using this
beautiful, original governor/vaporizer assembly.

Getting further into the engine I found that the piston rings
were shot, so I replaced them with new rings after running a ball
hone on the bore. I cleaned the engine with kerosene and fine steel
wool, leaving what was left of the original green paint and a nice

I re-shimmed all the rod and main bearings using copper and
brass shim stock. The basic engine is in pretty good condition, and
it was probably still running when it was taken out of service.

I ran the Junior, ironing out the carburetion and governing
bugs, but I still had to do something about that Japanese spark
plug that was firing the engine. All the Samson N Series engines
with one-piece igniters use the same igniter setup, so I removed
the igniter from my 5 HP Samson and transferred all its dimensions
to a print. I laid out the body dimensions on sheet copper and made
a template, and using that as a pattern I built the igniter body
from 3/4-inch thick steel plate. After about 12 hours of drilling,
grinding, welding, etc., I had an igniter. I then built the trip
rod and turned the locking collars, put it all together and fired
it up – it took right off and it works perfectly.

Only problem was, now everything was new and shiny on the
ignition system. That just wouldn’t do, so I went to a hobby
store and bought a bottle of ‘black brass’ solution. This
stuff colors brass black and it colors shiny steel like century old
cast iron. I found this out by accident, but it works wonderfully.
I used it on the Junior’s ignition system and it blends in
perfectly with the engine’s original patina.

Amazingly, the original nameplate was still on the engine, and
why it didn’t disappear along with the rest of the parts years
ago I’ll never know. Showing serial number N841, this engine is
probably from around 1904. It’s a beautiful running little
Samson Junior. It clicks, clacks and trips right along, and
it’s worth noting there are no counter balances on the
crankshaft or flywheels, yet it’s still a smooth runner.

There is one other item missing, which is the cast iron
pre-heater that draws warm air from around the exhaust pipe and
into the bottom of the fuel vaporizer. The correct pre-heater will
have a casting number with a ‘B’ prefix, and if you even
suspect you may have one I’d like to know about it as it would
complete this unique little Samson.

Contact engine enthusiast Lester Bowman at: 175 North Santa
Ana, Modesto, CA 95354.

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