Community Shop Talk

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Clogged Fuel Lines …

Stationary Engine List
By Helen French

The nearest I’ve been to a stationary engine for at least two
months is …. well, about 24 inches. But that doesn’t really count,
because that engine is the Fairbanks-Morse Eclipse scale model that
permanently sits on the kitchen counter, just behind my computer
monitor. Apart from that, it’s been too wet and cold to uncover and
run engines, and we even missed the local Christmas show for the
first time in five years due to pressures of work. However, it
seems luckier people have been able to get out to the shed to do
some real work!

In the past, a discussion on cleaning gummed-up old fuel and
loose rust from fuel tanks has appeared in this column for GEM. I
try not to repeat subjects covered before, but this one is more of
a continuation than a repetition.

• I need some list help to unclog a pipe in a gas tank. I am
working on a gas heater for soldering irons. The tank was full of
dried junk and I finally got it all out by shaking rocks inside for
quite some time.

However, the discharge pipe is also clogged. I have removed the
cutoff valve. The pipe is welded to the tank and is radiused inside
down to the bottom of the tank. Thankfully, this was done rather
than a right angle, as it makes it easier to push something down
it. I have tried forcing air, a number of wires, braided wire on
the end of a drill, etc., all to no avail. The pipe must be full of
dried junk. I now have it standing upright with carburetor cleaner
soaking in the pipe. Does anyone have any ideas on how to unclog
the pipe? It is 1/4-inch steel.

• I have used a section of speedometer cable in a drill with
good results in similar situations.

• If you use this method, cut off the end fitting, then open up
the last coil to make a hook.

• I’m guessing this is a gasoline-fired soldering iron? Old
gasoline will eventually dry into the caked gunk you describe. I’ve
had good success dissolving dried gas residue with lacquer thinner.
Fill it up and let it soak for a few days and it’ll be clean as a

• Yes, it is a gas-fired burner for soldering irons. Never seen
one like it before. I will try soaking with lacquer thinner. I
think the pipe must be solid for quite a ways up in it. It sucks
from the bottom and the tank was 1/4 full of dried junk. After
soaking for a while, I will try the speedometer cable in the

• I’ve always used denatured alcohol to dissolve varnished
gasoline. I just picked up a snow blower that had no spark. I
cleaned the points and got spark, but the carburetor and siphon
tube were all gummed up. I couldn’t get a brazing rod through the
tube, but a day in denatured alcohol did the trick. It runs

• I have always wondered if a person could add a few ounces of
denatured alcohol to the gas tank to help keep it cleaned out.
Would it hurt anything to do this?

• I don’t think it would hurt anything. After I cleaned out my
Ideal base with denatured alcohol, I could smell it when it was
running. But, if you run the engine even a few times a year, you
should have no problems. What better cleaner than gasoline? Why not
consider a fuel stabilizer for storage if you’re worried about it
gumming up?

• Since that is about all gas line antifreeze is anyway, go
ahead. Just be aware that if there is any water in the tank, or any
other crud, it will travel with the alcohol. I learned that the
hard way when my family went on a trip out west in the 1980s. First
tank of gasohol plugged the fuel filter six times. Nothing like
changing the fuel filter on the side of the highway and then having
to drop the tank to replace the fuel sock. I did get real good at
changing the fuel filter on that vehicle though.

• Maybe I will try 1/2 denatured alcohol and 1/2 lacquer

• I once mixed gasoline and kerosene in a smudge pot and lit it,
not realizing what was mixed. It worked okay until I picked it up
to move it. About liked to blow my head off! Luckily, the pressure
of gasoline igniting blew itself out.

• Is denatured alcohol in the U.S. the same as the “meths” or
“methylated spirits” we use in the UK? Ours is purple in colour and
is ethyl alcohol with methyl alcohol added to make it

• I have no idea what the UK calls things. I bought a can of
“solvent alcohol” at an estate sale – I figured it was “denatured
alcohol.” It smells, burns, and solvents the same, but the
ingredients are different. Denatured alcohol contains methyl
alcohol Cas no. 67-56-1 and ethyl alcohol Cas no. 64-17-5. Solvent
alcohol contains methanol – no other ingredients listed. So, even
over here, what I think is the same, is something else!

• That’s “methylated spirits,” and is the most common kind of
denatured alcohol here. But there are several other approved
ingredients for “denaturants.” The purpose is to make you sick as
hell if you drink it, so you won’t. If the alcohol’s non-drinkable,
the BATFE [Bureau of Alcohol, Tobacco, Firearms and Explosives]
exempts it from Federal liquor taxes.

As always, take care when using solvents. They are far more
effective at unblocking clogged pipes than they are at quenching
the thirst of a hard-working engine man – for that purpose, beer
has the added bonus of coming in a container that can be recycled
afterwards into shims for an engine. Who says this hobby isn’t
environmentally friendly?!

Engine enthusiast Helen French lives in Leicester,
Contact her via e-mail at:
You can join the Stationary Engine List on the Internet at:

… and Running on Propane

By Harry Matthews

• Well, I seem to have caught this propane bug that’s been going
around, and am toying with the idea of running my 6 HP M on the
bottle. I think I can make a plate for over the compensator and
plumb the bottle up there. I am hoping to be able to start the
engine on gasoline and after things warm up a bit I want to be able
to switch it over to propane.

What I need to know is this: Do I need to change the magneto
timing to run on propane, or will the same settings I use for
gasoline work for propane? It occurs to me that propane engines
don’t run well with the timing advanced, but I am not sure. –

• Joe, I ran my 6 HP M just the other week on propane. The
timing was still the same as when I run the engine on my special
mix (half lead-free gas and half paraffin). We always use a special
regulator when running an engine on propane. The engine was running
on kerosene and I put the hose in the opening of the damper plate
when it was closed, closed the kerosene needle valve and she ran on
propane without any trouble – but much slower and quieter. I opened
the damper plate just 1/8-inch and the engine ran like a clock. One
of these days I will make an adapter plate instead of the damper
plate with a built-in tube for the propane and a little adjustable
air inlet to regulate the mixture. – John

• I always start my propane-fired engines on gasoline, then
switch over to propane once they are running. On IHC M’s this would
be really simple to do, since you already have that priming bowl in
the mixer.

A trick I have found helpful is to shut off all possible air.
Only feed the engine propane and it will suck air from somewhere,
like around the valve guides. This way you only need the smallest
amount of propane to make your engine run. Propane has something
like 35 times the BTUs of natural gas and only needs a very
miniscule amount of air to combust. Once you have your M running,
turn your gasoline off and turn the propane on slowly. When you can
hear the propane “hisssssssss,” that’s more than enough. Make
something to go over the carb/mixer so it cannot suck any air. You
will be surprised at how long an engine will run on a 20 pound
bottle of propane when it’s done this way. – Doug

• John, how does the suction valve work? – Bob

• With an open bottle there will be no propane coming out the
hose; when you push the little brass pin the propane escapes. At
the inlet stroke the engine sucks the valve open and the propane
comes in the mixer, no more, no less. The faster the engine runs,
the more propane comes out the bottle. When you pull the hose out
of the mixer, then the flow stops immediately.

These regulators were used on the English Wolseleys, mostly for
the little milking units in the field. So now and then they show up
on the market, but they are scarce. With these valves you never get
propane gas when it is not needed, only when the inlet stroke is
there. One of my engine friends runs a Baker Monitor on propane
with the same valve unit. You can see the flywheels spinning very
slowly and hear a little hissing, that’s all. Some guys use an old
LPG car unit that works the same. – John

• On a hit-and-miss-governed engine that “demand” valve is
necessary. Valves like this are similar to what is used on
LP-powered tractors and forklifts. On a throttle-governed engine
this isn’t needed unless you plan to actually work your engine – if
you don’t want to work your throttler, but just make it run slow, a
demand valve isn’t needed.

You can simply use a regulator off a barbeque grille. Some
barbeque regulators have a valve inline after the regulator. This
way, you only have to turn the main valve on and feather how much
propane you want by the little inline valve. And since propane
burns so dry, it is a good idea to plumb in a drip oiler in the
fuel line itself. And remember, shut off all air intake as best you
can. – Doug

• Check with your local power company, and ask where they get
their propane-powered equipment serviced. The repair shop should
have the regulators you need. Especially when cool, you need to
preheat the engine before running on propane. There is also a 25
percent power loss, as well as a 25 percent more fuel used penalty
over gasoline. One more item – propane also increases wear
throughout the engine – valves, seats and rings, as propane runs
hotter and has no lubricating value, unlike gasoline. – Andrew

• I had real good luck running my 6 HP IHC M on propane. I used
a barbeque regulator and a hose I picked up at Lowe’s. I removed
the mixer/carb and made a plate that bolted on there, drilled and
tapped it for 1/4-inch pipe thread and put in a nipple and a tee.
On one side of the tee I put a ball valve to control the air, and
on the other side of the tee, I put a needle valve to control the
gas. Then I hooked the regulated flow from the bottle up to the
needle valve. I used the same timing settings as I would use on
gasoline. You will have to feel it out to see what air/gas settings
work for you, but with the help of a friend of mine we were able to
get it to run very slow. I think it is important to be able to
adjust the gas and air separately. – Joe

• You should not use a regulator that provides a flow of propane
when the fuel tank is turned on. All motor fuel
vaporizers/regulators lock up (no fuel flow) until the regulator
senses a vacuum from the engine. When it sees a vacuum, fuel flow
will start. If you are running this engine with the type of
regulator you are speaking of and the engine stops, you would have
a dangerous fuel leak. If you want to run LP, please use the right
equipment. – Kent

• I’ve hooked up my Ideal to run on propane and have had great
success in running it slow and steady. But that doesn’t make it
correct or safe. The barbecue regulators with a needle flow control
will work with no problems, but they pose a safety issue. You need
a regulator that has a “vacuum-controlled flow.” Otherwise, you’re
making a potential bomb. I swapped my Ideal back to gasoline until
I can acquire the proper regulator. I did notice that the engine
ran much hotter while just idling when operating under propane.
Probably not a major issue at idle, but I’m sure it’s a factor to
consider if a load demand is added. – John

• Some manufacturers built mixers that piped fuel straight into
the mixer without an “on-demand” regulator. Commercial was one such
manufacturer, and I think Western did the same. The danger of such
a setup has been greatly overstated. The amount of fuel to run a
mid-sized engine is very small, much less than required to fuel
your hand-held propane torch. – Rob

• I have run my engines for a number of years on propane. They
should always be run with an “on-demand” regulator. This works just
like a needle and seat and float in a carburetor – it stops the
flow of fuel when there is no demand. The on-demand regulators can
be purchased at your local propane dealer. Ask for model SD made by
Garretson Equipment Co. – Anonymous

SmokStak is an engine conversation bulletin board and is part of
the Old Engine series of websites that started in 1995 as “Harry’s
Old Engine.” Harry Matthews is a retired electronic engineer and
gas engine collector from Oswego, N.Y., now residing in Sarasota,

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