Manual
Display Symptom Probable Cause Recommended  
Action
50%
Decrease in 
EGT for one 
cylinder at 
low RPM
Low 
compression.
Check 
compression.
50%
Sudden off 
scale rise for 
any or all 
cylinders
Pre-ignition,
or
Normalize view,
or failed probe
Full rich and 
reduce power.
Change to 
Percentage view.
Check probe
Loss of peak 
EGT
Poor ignition or 
vapor in fuel 
injection system.
Have magneto 
tested.
no sharp
peak
Decrease in 
peak or flat 
EGT 
response to 
leaning 
process
Detonation. 
Usually the result 
of 80 Octane fuel 
in 100 Octane 
engine.
Enrich mixture, 
reduce power and 
relean mixture. 
Repeat to find 
power setting 
where normal 
peak is obtained 
or run rich.
50%
Below 
10,000 ft. full 
throttle 
causes 
EGTs to rise
Weak or 
defective 
mechanical fuel 
pump.
Apply booster 
pump. If EGTs 
drop, replace fuel 
pump.
50%
CHT more 
than 500°, 
EGT normal. 
Adjacent 
EGT may be 
low
Leaking exhaust 
gasket blowing 
on CHT probe.
Look for white 
powder around 
cylinder to 
determine leak 
area.
Alarms
The EDM-760 has programmable alarms. When a measurement falls 
outside of its normal limit(s), the digital display will flash with the value 
and abbreviation of the alarming item. If the condition triggering the alarm 
returns to within normal limit(s), the display will stop flashing the alarm. 
Page 26 Engine Data Management










