False Peaks; Leaning On The Rich Side Of Peak - Electronics International UBG-16 Operating Instructions Manual

Next, slowly lean your engine by pulling the mixture out a very small amount. When the increase in
temperature slows to less than one degree per second, once again lean the engine a very small amount.
The slower you lean, the more accurate the results will be.
When any cylinder reaches its peak (hottest) EGT and starts to decrease
in temperature, the digital display will blink the word "PEAK" in the left
portion of the display and the hottest (Peak) EGT reached will be displayed
in the right portion of the display. The cylinder number inside the lit box at
the top of the columns is the first cylinder to reach peak EGT. That cylinder
number will blink, indicating the cylinder is now operating on the lean side
of peak. Also, the external warning light will blink.
Push the Step Switch to the right or left to acknowledge the peak and to stop
the blinking of the word "PEAK" in the digital display as well as the blinking
of the External Warning Light. At that time the current EGT will be
displayed in the right portion of the digital display.

1. False Peaks:

1. False Peaks: 1. False Peaks: 1. False Peaks: 1. False Peaks:
As you lean your engine, a dip in an exhaust gas temperature could occur for many reasons (e.g., mixture
linkage issues, non-linearity in fuel servo or carburetor mechanism, a small change in the pitch of the
aircraft, a small change in the air distribution as the engine torque and/or RPM changes, etc.). This dip in an
EGT can cause engine analyzers to indicate a false peak.
After the Peak EGT is found, continue to lean gradually. If the Peak EGT indication is actually only a dip
(false peak), the EGT will once again start to increase. When it increases above the false peak the UBG will
switch back to the leaning mode (the left portion of the digital display will show "LEAN"). This capability
is essential in eliminating false peaks.

2. Leaning on the Rich Side of Peak:

2. Leaning on the Rich Side of Peak:
2. Leaning on the Rich Side of Peak: 2. Leaning on the Rich Side of Peak: 2. Leaning on the Rich Side of Peak:
Once the first cylinder to reach peak is found and you have stopped the blinking by pushing the step
switch, enrichen the mixture and push the Mode Switch to the left to cause the digital display to show
the Temperature Below Peak EGT for that cylinder (e.g., "PEAK -
25"). Displaying the Temperature Below Peak EGT makes it very
easy to set the mixture to a specific EGT on the rich (or lean) side
of peak.
Note: Note: Note: Each time the Mode Switch is pushed to the left, the right
Note: Note:
portion of the digital display will alternate between displaying the
current EGT and the Temperature Below Peak.
Note: As you enrichen the mixture, the exhaust gas temperatures of all Note: Note: Note: Note:
of the cylinders will decrease. This will cause the cylinder num-
bers above all of the columns of bars to blink. A blinking cylinder
number indicates that cylinder's EGT has decreased from the
highest temperature it achieved.
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