GAS, OIL AND ALCOHOL ENGINES 427 



Before the engine is started, weigh the brake on the 

 scales with the friction part on wheels ready for the test. 

 Measure the distance from the center of the wheel to the 

 point where the brake rests on the scale. In a rope brake 

 the brake arm is the radius of the wheel plus half the 

 thickness of the rope. 



When everything is ready start the engine and gradu- 

 ally draw up the brake. A gasoline engine is running 

 at full load when it misses only one explosion out of 

 about every eight. Tighten the brake until this point is 

 reached, then run the weight out on the scale beam until 

 the point is reached where it balances. Now let one man 

 keep the scales balanced by tightening and loosening the 

 brake ; at the same time let the other man take the speed 

 of the engine for one minute. This is all the data needed 

 to determine the brake horse power. It is well, however, 

 to keep the brake on with engine running at full load for 

 at least 15 minutes to determine whether the engine will 

 carry the load. 



569. Care of gasoline engines. In the care of the en- 

 gine there are three points of equal importance, namely : 

 cleanliness, water, and oil. To secure the first a well- 

 lighted room is required, one in which the engine alone 

 is placed. Damp, dark cellars should be avoided. As to 

 water and oil, the consideration given depends entirely 

 upon the man in charge. If the engine room is light, the 

 floor clean, waste in a can, tools in a case, and engine 

 bright and clean, it is a certainty that its bearings do 

 not cut for the want of oil, nor its water jacket run dry 

 or freeze up. 



A person who does not understand the engine should 

 refrain from tampering with it as long as it runs well. 

 During this time he should be observing and notice the 

 workings of all parts so that in case the engine is not 

 working satisfactorily he can readjust it. 



