You may see, hear, smell, or feel the warning of trouble to come. Of course, common sense is also a requisite. Another factor in your success as a troubleshooter is your ability to locate the trouble once you decide something is wrong with the equipment. Then, you must be able to determine as rapidly as possible what corrective action to take. In learning to recognize and locate engine troubles, experience is the best teacher.
Instruments play an important part in detecting engine troubles.
You should read the instruments and record their indications regularly. If the recorded indications vary radically from those specified by engine operating instructions, the engine is not operating properly and some type of corrective action must be taken. You must be familiar with the specifications in the engine operating instructions, especially those pertaining to temperatures, pressures, and speeds. You should know the probable effect on the engine when instrument indications vary considerably from the specified values. When variations occur in instrument indications, before taking any corrective action be sure the instruments are not at fault before you try corrective actions on the engine.