Jerry E. Howell Model Project Plans & Kits
Outpost Enterprises, LTD - 695 Godfrey Road - Hollansburg - Ohio 45332 - USA
(World Wide Supplier of Quality Model Project
Plans & Kits Since 1992)
Model Stationary Engine Fuels
Fuel selection for our engines can be a problem. Some use
the same gasoline that is used in their cars. My friends and I
have tried this, but it really stinks when burned in our model
engines. This is probably due to the low temperature that these
engines operate at (especially the hit-n-miss) and the somewhat
rich mixture required by smaller engines. We came to the conclusion
that it also carbons up the valves and spark plugs far worse than
the camp fuel we had been using.
Most model engine owners are using Coleman Camp fuel with good
results. My Plunket Jr. engine (not a hit-n-miss) has higher compression
than many model engines and I noticed that it made some strange
knocking sounds that were not mechanical, so I decided it must
be detonation. Wondering what the octane rating is, a friend called
Coleman and was informed that the octane rating is only 53. No
wonder that it knocks! Knowing that methanol (used in may race
cars) has a very high octane rating and burns clean, in 1999 I
went looking for a source and found it at an automotive speed
shop. My Plunket Jr. and PowerHouse engines love running on alcohol!
Valves and plugs stay clean, and there is no more knocking, but
cold starting can be somewhat difficult.
I continued using the Coleman fuel in my antique model hit-and-miss
engines because they are lower compression and don't knock on
the low octane camp fuel. Over time, I finally became disgusted
at the fine lint particles in the Coleman fuel which was causing
all maner of problems maintaining a proper needle setting over
a period of time. I began filtering the fuel and installing in
line fuel filters on my engines. One day while at a Walmart store
around 1997, I noticed they had camp fuel called Ozark Trails
on the shelf next to the Coleman fuel. I decided to try a can
and see how it compared to the Coleman fuel. Upon checking, I
discovered that it was clear as water and had no trace of lint
particles. It ran just fine in all my hit-and-miss engines. I
told my friends about the Ozark Trails fuel and they gave it a
try. Now they use it too and we all agree that it even has a better
exhaust smell than the Coleman.
One day I got to thinking about the fuels I was using. The camp
fuel is easy starting but carbons the valves and plugs, while
the alcohol burns clean but can be hard starting when the engine
is cold. I wondered if I could blend the two together and get
the best of both. I discovered that up to 30 parts Ozark Trails
camp fuel will blend with 70 parts of methanol. Any amount of
camp fuel over 30 percent will not mix and will stay seperate.
An engine will start just as easily with this blend as with straight
camp fuel. After running the 70/30 methanol/Ozark Trails fuel
for more than 100 hours, I found that the valves and plugs stay
really clean. The spark plugs in my Plunket Jr. and PowerHouse
engines run almost a frosty white, no carbon deposits at all!
The fuel needle setting needs to be a little richer and a tank
of fuel will not run quite as long as camp fuel, but this could
hardly be of concern. The methanol raises the octane rating of
the blend to a high level. I think it is the best of both worlds,
as they say. Don't use these fuels in your lawn mower or car,
models only!
Addendum October 2006 - I have been
running the 30/70 fuel in my V-Twin engine since it was built
in 2003 and also in my new V-Four engine. After many hundreds
of accumulated total running hours in all my engines, I have found
no negatives at all with this fuel blend, only positives.
Addendum June 2008 - Wal-Mart discontinued
the Ozark Trails brand fuel earlier this year or late last year.
If anyone finds a good substitute (not Coleman) please let me
know. I am now running straight methanol in all of my engines.
If you decide to use Coleman camp fuel, you should at least strain
it through a couple of coffee filters to remove the lint.
© Copyright 2000 - 2008 Jerry
E. Howell - All rights reserved