THE ENGINE PROPER 75 



where it passes through the stuffing-box, it will be best 

 to procure a new stem. 



A governor should hold down the speed of the engine 

 and not allow it to "race" or "run wild," even with no 

 load and full boiler pressure. When a governor, which 

 once controlled the speed properly fails to do so it is an 

 indication that either its action is interfered with by an 

 imperfect stem or the like, or else that the valve and lining 

 have become worn so that sufficient steam leaks through 

 to cause the engine to race. Sometimes when this is the 

 case, the engine "dies" when called on to pull a heavy 

 load (as in sawing) on account of the fact that it is 

 screwed down too far in the attempt to control the speed 

 with no load. The remedy for this trouble is a new valve 

 and new lining or valve-seat. The length of time that a 

 governor will run before leakage through the valve be- 

 comes troublesome varies greatly from only a season 

 or so to perhaps ten or twelve years, depending on the 

 purity of the water. 



Rated Horse-Power. Stationary engines are rated at 

 about their actual horse-power, as determined by brake 

 test. Farm and traction engines, on the other hand, have 

 been rated very much below their actual or brake horse- 

 power, which is to be regretted. As the practice of under- 

 rating has existed since engines for driving threshing ma- 

 chines were first built, and has grown up with the busi- 

 ness, it is somewhat difficult to change this at the present 



