22 SCIENCE OF SUCCESSFUL THRESHING. 



trouble. This is done by removing the steam chest heads 

 through which the starter-pins pass, and unscrewing the 

 valve, which is done by holding one end while unscrewing 

 the other, by means of the two special socket wrenches fur- 

 nished for the purpose. If the pump has been idle for a 

 time, the valve may be rusty or gummy, in which case it 

 should be cleaned with kerosene oil. Before replacing the 

 caps, push the valve back and forth as far as it will go and 

 see that it is perfectly free. Also see that the starter-pins 

 are free and are not stuck by tight packing or have become 

 loosened. Pull them out as far as they will go. 2. The 

 steam pipe may be obstructed so that the pump does not re- 

 ceive a sufficient supply of steam. A screen gasket is placed 

 in the steam pipe union in order to prevent scale or chips, 

 in a newly connected pipe, from reaching the pump. If 

 steam does not reach the pump, this screen should be ex- 

 amined as it may be partly or entirely clogged. When the 

 pipe has been thoroughly blown out, this screen gasket may 

 be removed and a plain rubber or lead gasket used. 3. Re- 

 move the cylinder heads and see that the piston moves freely, 

 and that the nut on the water end of the piston rod is prop- 

 erly tightened. This nut may have worked partly or entirely 

 off, thus preventing a complete stroke. 4. Remove the 

 steam chest and see that the small "trip" holes near the steam 

 chest and the corresponding holes in the steam cylinder are 

 open. If the pump has been idle for a time, these holes 

 are liable to have become stopped with rust. Before 



