THE BOILER 113 



other serious damage to the engine. It always washes the 

 oil from the cylinder and valve, thereby causing the latter 

 to squeak. The lubricator or oil pump should be allowed 

 to feed quite freely after priming, or serious injury to the 

 valve-gear may result. 



Painting the Boiler. The greater part of the boiler can 

 be kept black and looking well by rubbing with oily waste 

 or rags. The front end of the boiler, around the smoke- 

 box, and the smoke-stack require painting from time to 

 time to prevent them from becoming rusty and unsightly. 

 For this, asphaltum (which may be thinned with turpen- 

 tine or benzine), or boiled linseed oil mixed with a little 

 lamp black, is suitable. The entire boiler may also be 

 painted with either of these when necessary. 



Cleaning the Boiler. No fixed rule can be given as to 

 the frequency with which a boiler should be washed out. 

 In some localities it is necessary to clean it twice a week, 

 while in others, where the water is almost perfectly clean 

 and pure, once in six weeks is sufficient. In emptying the 

 boiler preparatory to cleaning, be sure that all of the fire is 

 out, and that the steam pressure is below ten pounds before 

 opening the blow-off valve. This is necessary, in order to 

 prevent the mud from becoming baked on the tubes and 

 sheets. See that the fire door, smoke-box door and drafts 

 are all closed to prevent the boiler from cooling too quickly. 

 To clean the boiler, remove the plugs or hand-hole plates 

 in the water-leg and also the one at the bottom of the front 



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