Operation And Care Of Two Cycle Engines - Viking Vagabond Operator's Manual

OPERATION AND CARE OF TWO CYCLE E NGINES
FIRST, GET ACQUAINTED
Understanding how a two-cycle engine operates helps
you understand why it needs the right diet of gasoline
and oil, why it needs the right spark plug and why
engine manufacturers tell you, "Don't baby it." Much
of the information you want is in the pages that
follow, but you have some other "must" reading as
well - the operators manual that comes with your
engine. Read it - and understand it - before you
start your engine.
A two cycle engine differs from the four-cycle in
your automobile or in your garden tractor.
*It uses a gasoline-oil mixture for combustion and
lubrication, not gasoline and oil separately as in
your automobile engine.
*It fires on every second stroke of the piston.
Every down stroke of the piston is a power stroke
12.
- a power stroke for every revolution of the
crankshaft.
When a piston in a two-cycle engine moves upward in
the cylinder (its first stroke), it draws a charge of fuel
into the crankcase below and at the same time
compresses the fuel in the combustion chamber above.
As the piston completes the up stroke, the spark plug
ignites the compressed fuel and the burning fuel
expands and forces the piston downward (second
stroke, or power stroke). In this down stroke, the
piston not only provides power to turn the crankshaft
but also compresses the new charge of fuel in the
crankcase, then, as it continues downward, it clears
the transfer ports in the cylinder wall, releasing the
new charge of fuel through the ports and up into the
combustion chamber where the new charge displaces
the burned gasses, forcing them out through the
exhaust port.