Electronics International TC-1P - Manual (Page 9)

Operating Information EGT's
EGT's
1. Using an EGT Analyzer to Lean Your Engine:
To properly lean your engine, using a multi-channel analyzer, perform the following steps:
A. Rough Leaning: Select the hottest EGT cylinder. Adjust the mixture control from the full rich
position to a leaner setting that results in a slight drop in engine RPM or to a setting near peak EGT, as
dictated by experience. The mixture control should be left at this setting until the EGT’s stabilize. It
will take about 20 seconds for the temperatures to stabilize within 1`F. This lag is due to the combus-
tion walls and piston domes increasing in temperature, which affect the combustion and exhaust gas
temperatures. To correctly lean an engine you must wait for the engine to thermally stabilize. Less
sensitive gauges will not pick up these subtle changes, which are important in leaning and diagnosing
problems.
B. Precision Leaning: Again select the hottest EGT cylinder. This cylinder may be different than the
one you started with. This is the cylinder on which you should perform your precision leaning. Again,
start leaning, making only very small adjustments and waiting 3 to 5 seconds between adjustments. As
you approach peak, the exhaust gas temperature will rise much slower until it starts to decrease. When
this happens you have reached peak EGT. The 1`F resolution of the digital display will be invaluable in
helping you precisely detect peak EGT.
C. Finding The Cylinder That Peaks First: For most engines Step B (Precision Leaning) will result in a
properly leaned engine. If you find this to be the case with your engine, this step will not be necessary.
But if you want to verify that you have leaned to the cylinder that peaked first and your engine is
operating properly, perform the following with the cylinder found in step B at peak EGT: Slightly
enrich the mixture and quickly step through each cylinder. Any cylinder that shows a rising temperature
is a leaner cylinder. Check that this cylinder does not rise more than 15’F before it starts decreasing in
temperature. If a cylinder rises more than 15’F it may have a problem.
2. EGT Diagnostics:
Since the EGT is directly related to the combustion temperature, it is an indication of the engine’s ability to
produce power. If the engine is not producing the correct amount of power, the EGT instrument can be a
very valuable troubleshooting tool as well an early warning system before engine failure occurs. With 1‘F
resolution, our digital EGT instruments will react to the slightest changes in the combustion process. To
detect a problem, become familiar with your engine’s normal EGT readings during run-up, climb, cruise and
descent. Any difference from the norm can be a sign of trouble.
During normal operation the EGT will stabilize to 1‘F for a given throttle and mixture setting. If it does not
stabilize, this can also be the first sign of trouble. With rate and trend information being displayed instanta-
neously and with temperatures being read to 1‘F, few problems can escape the pilot flying one of Electronics
International’s analyzer systems.
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