Download 2 cycle

Ag Mech.
2 and 4 Cycle Engines Strokes
4 cycle
Intake, compression, power, and exhaust functions take place during four strokes
of the piston (two revolutions of the crankshaft).
Intake stroke
Intake valve is open. Exhaust valve is closed. Piston is moving downward,
creating a vacuum in the cylinder sucking air/fuel mixture.
Compression Stroke
Intake and exhaust valves are closed. Piston is moving upward compressing
air/fuel mixture.
Power Stroke
Intake and exhaust valves are closed. Spark plug ignites. Air/fuel mixture
explodes pushing piston downward.
Exhaust Stroke
Intake valve is closed. Exhaust valve is open. Piston is moving upward,
pushing burnt air/fuel mixture to the muffler.
2 cycle
Intake, compression, power, and exhaust functions take place during only two
strokes of the piston (one revolution of the crankshaft).
Piston moves up, crankcase pressure drops and the intake port to crankcase is
opened. Air/fuel mixture enters the crankcase and air/fuel mixture in cylinder
is being compressed.
Piston moves down due to explosion from combustion of fuel mixture creating
an increase of pressure in crankcase. As piston nearly finishes downward
stroke, intake port opens to the cylinder and exhaust port opens to muffler
exchanging gases in the cylinder by the piston pushing new air/fuel mixture
into cylinder.
The Complete Magneto Cycle
When the permanent magnet moves away from the coil, it has little or no effect
on the coil. But as the magnet comes closer, the primary winding of the coil
"feels" the increasing magnetic field. The coil is being acted upon by the
magnetic lines of force, therefore, current flows in the primary circuit. This
current passes through the breaker-points and into the ground. When the
permanent magnet moves some more, the magnetic field is reversed and
induces low voltage in the primary coil. At this point the piston is reaching
the top of its stroke and is compressing the air-fuel mixture. The breaker
points open, causing primary magnetic field to collapse at an extremely high
rate through secondary windings. This induces high voltage which is required
to fire the spark plug. Spark plug fires and condenser discharges voltage back
into primary circuit.