356 FARM MOTORS 



keeping the boiler warm, and in the morning there will 

 be a good bed of coals which will start up readily. When 

 a boiler is being used daily, it is considered more econom- 

 ical to bank a fire than to let it go out and then rekindle it 

 in the morning. 



492. Drawing a fire. Fires are drawn when it is de- 

 sired to cool the boiler down very quickly or when the 

 water is dangerously low. A fire should never be drawn 

 without first smothering it with ashes, dirt, or fresh coal. 

 Drawing a fire without first doing this causes it to glow 

 up, and for a moment become much hotter than before 

 it was stirred. Never put water in a furnace, as it is 

 liable to crack the grates. It will also produce so much 

 steam that it will either blow back or else blow the fire 

 out the door and make it too hot to work around. 



493. Priming. When water is carried over from the 

 boiler with the steam the boiler is said to be priming. 

 Priming can always be detected by the click in the engine 

 cylinder, which shows that there is water there. Taking 

 too much steam from the boiler at once, carrying too 

 much water, or not having enough steam space will cause 

 priming. If the cause is too much water, blow out some 

 and then slowly start the engine. Carrying a high steam 

 pressure and keeping the water as low as possible will 

 retard priming to a certain extent. 



494. Foaming is similar to priming, but it is generally 

 caused by dirty or impure water. It can be detected by 

 the rising and falling of the water in the gauge glass and 

 by the engine losing power or speed ; also by the clicking 

 in the cylinder. When a boiler foams, the engine should 

 be shut down at once and the water in the boiler allowed 

 to settle. So much water is carried over in the steam 

 that the glass does not show the true level. If after 

 settling down it is found that there is plenty of water over 



