748 SUCCESSFUL FARMING 



the engine begins to operate below the rated speed, the exhaust valve closes 

 and a charge of air and gas is drawn into the cylinder through the car- 

 buretor. This type of governor, of course, gives an uneven speed, but 

 it is all right for ordinary agricultural purposes. It would not do for 

 furnishing electric lights direct from the dynamo, because the lights would 

 flicker with every variation in speed. This type of engine would do for 

 charging batteries from which lights may be taken. 



The throttle governor regulates the amount of air and gas mixture 

 which enters the combustion chamber. This is done automatically in 

 the stationary engines. This type of governor may be relied upon to 

 give a more even speed than the preceding one, and especially is this true 

 if extra heavy flywheels are used. 



Gas Engine Troubles. — Gas engine troubles are almost unlimited. 

 They are generally from two causes: the things we forget and the things 

 we don't know. Troubles most frequently occur in the ignition system 

 or from lack of proper lubrication. The first is easily remedied, but the 

 latter usually means a new part. If dry batteries are used they may 

 become wet and deteriorate, or a connection may be loose in the wiring. 

 A drop of oil or water may be over the point of the spark plug. Points 

 of the spark plug maj^ be too far apart or too close together. There may 

 be a loss of compression due to leaking valves or piston rings which do not 

 fit tightly against the walls of the cylinder. Leaking may take place also 

 around the spark plug or igniter. The mixture of air and gas may not be 

 proper, in which case, either the gasoline supply is not regular or the air 

 is not properly supplied. In cold weather the fuel often refuses to 

 vaporize. Such a condition may be remedied by pouring hot water in the 

 water jacket in order to warm the cylinder enough for good vaporization. 



TRANSMISSION OF POWER 



The best farm motor on the market is of no value on the farm unless 

 the power which it develops is transmitted to some other machine doing 

 useful work. Power is transmitted by shafting, belts and gear wheels. 

 While there are other methods of transmitting power, they are only 

 modifications of these three. 



Shafting. — The shafting should transmit to the pulleys which it 

 carries whatever energy it receives minus the amount consumed by fric- 

 tion at its own bearings. Shafting should be of the very best material 

 in order to reduce the friction in the bearings by reducing the size. It 

 should be absolutely straight, because much power is required to spring 

 even a two-inch line shaft into line during each of two hundred or four 

 hundred revolutions per minute. A shaft should be driven from the 

 center if possible and between two bearings, and transmit its power to a 

 series of pulleys on either side of the main drive. If possible, heavy shafts 

 should have their bearings or hangers rest upon posts which are directly 

 connected with the ground, because there is always more or less "give" 



