Troubleshooting a Two-Cycle Engine

By Staff
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A collection of Maytag two-cycle engines belonging to Stan Read of Gunnison, Colorado
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An Oshkosh two-cycle hopper-cooled engine, maker and year manufactured unknown.  

Let me continue the discussion I started in
the Sep-Oct ’67 issue of Gas Engine Magazine on troubleshooting a two-cycle engine.

The little Maytag engines are fairly easy to find and if one
does not have too much room for collecting the bigger engines they
provide an interesting example of design used on many of the larger
two-cycle engines. Most present day two-cycle engines use the
reed valve–a thin metal strip covering a machined opening–to
allow the fuel-air mix to enter the crankcase and prevent its
escape. The vertical Maytag built from 1914-1923 used a brass
poppet-type valve to perform this function, and it was located in a
small brass carburetor or mixer which also contained a needle valve
to regulate the fuel-supply. The later horizontal one-cylinder
Maytag used the same type system but more refined in design. The
two-cylinder horizontal Maytag used a crankshaft port valve.

Maytag’s horizontal engines used the flywheel type magneto
similar to most present day small engines. The points are operated
by a centrifugal weight type governor which should prevent point
operation beyond 1000 to 1050 RPM.

Points should be set to .020 inch on the horizontal Maytag
engines, which should properly time them also. If timed properly the
points should just begin to open when the piston is one-fourth inch
from the top of its stroke outward. Some of the earlier one
cylinder models had timing marks on the flywheel which aligned with
marks on the plate behind the fly wheel.

Timing is more particular with two-cycle engines than with the
four-cycle type since a degree of error at the fly wheel with two
cycle operation is a degree of error in ignition, but with four
cycle operation represents only a one-half degree of error at the

Cylinder carbon deposits which raise the compression to the
point of ignition can cause poor performance and overheating, which
sometimes is mistaken for improper timing. With ignition-governed
engines such as Maytag this can also cause “runaway,” since
ignition becomes independent of the governed electric system.
Carbon troubles can be remedied by occasionally cleaning out the
combustion chamber and/or leaning the fuel mixture a little at a
time until a minimum of smoking occurs at the exhaust. Reducing the
oil in the fuel may be required but too much reduction may cause
lubrication failure.

I have a 2 or 3 HP hopper cooled, two-cycle Oshkosh engine. (see
picture) None of the directories I have list this engine so I do
not know where or when it was built or by whom. Do any of you have
any information on the Oshkosh? H. C. Doman, Star Foundry &
Machine Co., Termaat & Monahan Co., and U. S. Engine Works all
built engines at Osh-Kosh, Wisconsin.

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