144 SCIENCE OF THRESHING. 



it should be done by the governor; this will allow the 

 engine to run at the desired speed without fear of 

 being run too fast. 



GUIDING THE ENGINE. 



When traveling on the road, the engine is made to 

 turn by swinging the front axle as in a wagon, by 

 means of the guide wheel and steering chain gear. 

 By cramping the wheels more or less, a longer or 

 shorter turn is made. 



To find the space required to turn the engine 

 around completely, when the front wheels are 

 cramped at a given angle or position, set the wheels 

 at the required angle and then draw a line on the 

 ground beneath and in a line with the front axle, also 

 draw a line under and in line with the rear axle. The 

 intersection of these lines will be the center of the 

 circle in which the engine will travel when the wheels 

 are set in a given position and double the distance 

 from this center to the engine will be the diameter or 

 width of the circle. 



THE FRICTION CLUTCH. 



To set the train of traction gearing in motion, and 

 thus start the engine traveling, the flywheel is first 

 put in motion and then the friction clutch is thrown 

 into engagement with it. The motion of the engine 

 shaft is thus transmitted through the clutch and gears 

 to the driving wheels. In using the friction clutch, 

 care should be taken not to throw it in gear too 

 suddenly, as the strain on the gearing and connections 



