J.P. Instruments EDM 900 Pilots Guide - Manual (Page 25)

For Your Safe Flight Page 25
The following depicts the power, mixture and temperature relationships.
The following pages provide step by step guidelines in leaning your
engine, for both rich of peak and lean of peak modes:
As the mixture is leaned, EGT rises to a peak temperature, and then
drops as the mixture is further leaned. Peak power occurs at a mixture
using more fuel than at peak EGT. Best economy occurs at peak EGT.
Accurate leaning yields optimal engine temperatures. By being able to
precisely adjust the mixture, your engine can produce either the best fuel
economy or maximum power, whichever you choose.
A single EGT gauge merely gives you an average of a few
cylinder’s temperature: some cylinders can be too rich, while others too
lean. Variations produced by differences in fuel distribution, ignition, and
compression will cause each cylinder to peak at a different temperature.
In some cases the coldest cylinder will peak first. TIT will run up to 100
degrees hotter than the hottest EGT.
E
G
T
°F
b
e
lo
w
p
e
a
k
P
e
rc
e
n
t
o
f
b
e
s
t
p
o
w
e
r
C
H
T
°F
c
h
a
n
g
e
fr
o
m
b
e
s
t
p
o
w
e
r
Best
economy
range
Best
power
range
0
-200
-100
-300
-20
20
-60
-40
0
-80
100
85
90
95
80
EG
T
CH
T
Perc
ent p
ower
Sp
ecif
ic
fue
l co
nsu
m
ptio
n
Over
lean
Lean Rich Full Rich
(Take-off)
Leaner Mixture
Peak
Power
First cylinder
to peak. Use
Rich of Peak
leaning
Last cylinder to
peak. Use Lean of
Peak leaning with
GAMI injectors
GAMI
spread