522 ENGINEERING ON THE FARM 



position. Oil gets to the cam shaft and connecting-rod 

 bearings by flooding over the surface and leaking into the 

 bearings. The most improved splash systems are provided 

 with an oil pump or well from which a pump continually 

 delivers fresh oil to the dip pan. In the force-feed system 

 the crank shaft is drilled ; oil is conducted to rings at one or 

 more of the bearings of the crank shaft, whence it is forced 

 through the hole in the crank shaft to be delivered directly 

 to the center of the connecting-rod and crank-shaft bearings. 

 The direction of movement of oil on the bearings in the 

 force-feed system is from the center of the bearing outward, 

 while with the splash system the oil works inward from the 

 outside of the bearing. The force feed provides the surest 

 and most efficient lubrication. Most of the better engines 

 use a combination of the systems. In this scheme the main 

 bearings are oiled by force with a surplus of oil. The extra 

 oil collects in dip pans and is thrown to the piston, cylinder 

 walls, and cam shaft. 



LOCATING ENGINE TROUBLES 



When an engine stops and refuses to start, attention 

 should be turned first to the gasoline system. Leaks in 

 the gas tank or connections may occur, or a float become 

 "hooked up" in the carburetor or vacuum tank. Water or 

 dirt in the gasoline may clog feed pipes, screens, or valves. 

 Next the ignition should be carefully examined, spark plugs 

 tested by means of turning the engine over and short-cir- 

 cuiting with a metal tool provided with a wooden handle, 

 and battery connections tightened if found to be loose. 

 When the engine is turned over to test the spark plugs, a 

 piston which has stuck or faulty compression will be readily 

 detected. 



In case of lack of power some attention should be given 

 to the parts above mentioned, as an obstruction in the feed- 

 ing system or weak and uncertain ignition may be the source 

 of trouble. The mixture of air and gas delivered by the 



