404 



FARM MOTORS 



FIG. 282 COMPRESSION AND IGNITION STROKE OF FOUR-CYCLE ENGINE 



or two complete revolutions of the crank are necessary 

 to complete this cycle, hence the name four-cycle. These 

 strokes may be enumerated as follows : The piston makes 

 one forward stroke, drawing into the cylinder through 

 the irrlet a charge of fuel and air. This is called suction 

 (Fig. 281). A second stroke compresses this charge 



FIG. 283 EXPANSION AND RELEASE STROKE OF FOUR-CYCLE ENGINE 



