ENGINE TROUBLES.--When we come to consider the engine troubles, so-called, we shall find there are legions of them. In these days many of the troubles are easy to remedy, but to remedy them means that the causes of troubles should be understood. A physician cannot prescribe for a disease until he has made a diagnosis. Sometimes the difficulty will be recognized by the symptoms, and is easily adjusted. But suppose the firing is all right, and the engine fails to pick up, and seems to be dying out, it may be attributable to several causes, either one of which would account for it. DIFFICULTIES POINTED OUT.--If the engine seems to run down, and fails to pick up quickly, it may be due to water in the carbureter, or to a weak battery, or to leaks in the water jacket that will admit water into the compression chamber, or the trouble may be faulty compression. Other things should be looked up: The pump may be out of order, the connections loose, and thus permit waste through the leaks, or there may be a stoppage somewhere in the water circulation, or the water may be exhausted, or the gasoline too low or too poor for the kind of carbureter which you have. If anything is due to the engine itself, in the vast majority of cases, it is due to poor compression. The engine is too often blamed for faults which belong elsewhere. Nevertheless, it is well carefully to examine the bearings, to look over the clutch, and the bearings in the line leading to the drive shaft. STARTING THE ENGINE.--In starting, some engines give a great deal of trouble, usually due to wrong adjustment of the sparking device. This should not be advanced too much. If the trouble is not at that point, it may arise from too weak a suction, or an obstruction in the carbureter itself. CARBURETER.--At slow turning speed of the engine, the carbureter is very sluggish, because it must be started up from a condition of repose, and unless there is the best of compression, the suction will not be sufficient to dislodge or move the slightest impediment which may be in the way. LOW COMPRESSION.--Low compression arises from numerous causes. A carelessly screwed sparking plug; defective or partly blown out gasket in the cylinder head; loose, or partly open compression cock; a sticking valve; a rusted, or defective inlet valve; leak in the combustion chamber; or a worn or scratched cylinder. Whenever it is possible, the engine should be examined to observe the condition of the piston rings. Sometimes the rings will break into small pieces, and these parts will wear the most perceptible creases in the cylinder walls. When such is the case they will have to be taken out and lapped.