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EGT ISSUE

P

Pat Stewart

Well Known Member
Today while flying I noticed that when I pull the throttle back to around 5000 my EGT goes up to 1450-1470. When I bring the power back up to 5300 to 5500 the EGT drops to around 1390-1400. The CHT's stay around 190-200 and the oil temps around 185. If this is normal then any time I want to fly in the 5000 rpm range my EGT will approach the yellow line.

Any feedback from those who have been flying for a while,
 
I wonder if related to diaphragm carbs that self adjust mixture for altitude? Maybe when you pull throttle back the mixture leans a little bit. Just conjecture on my part?
 
RFSchaller said:
Are you sure about these numbers?
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Yes, sure about the numbers, my assumption is as Piper J3 responded but wanted to verify with those flying the 12.

It is very much like leaning a Lycoming with mixture control only on the 12 there is no mixture control.
 
Pat,

Today I watched my EGTs when I made power changes, and you are right they go up as I reduce power! Never noticed that before. I guess as long as they were in the green I don't care what the valu is.

One comment though. My EGTs typically run 1220 F to 1275 F on left and right respectively. Your values seem high.

Rich
 
Before reacting to EGT temps, remember that the placement of the probe in the exhaust pipe greatly influences the actual reading. Also, the probes are notoriously unreliable. My left one is steady while my right one jumps all over the place. I'm quite sure my engine isn't doing anything funny. It's just the probe. Unless they go Red, I' wouldn't worry about it.
 
Pat, check your connectors. Once I soldered mine, this exact problem went away and never returned.

Rick.
 
Pat on the bottom of each carburetor is a mixture screw. It should be turned out one and a half turns from full in position. Did you check them during installation? If not that maybe the cause for the higher EGTs. You will have to remove the carbs to get to the screws. You may be able to just remove the air cleaners, loosen the rubber boot hose clamp and pull and twist the carb to access the screw without removing the throttle and choke cables thus not needing to re-balance the carbs.;)
 
I have had a persistently high Right EGT...I just replaced the right probe...in the middle of my annual now....so let me know if adjusting that mixture screw fixes it.

I just assume the right one is higher due to the closeness to the oil tank.
 
FWIW at the ROTAX course I took the instructor said messing with the factory setting on the mixture was a frequent cause of business for him to straighten out an owner's tinkering. Not saying you can't adjust it, but you may be causing yourself more problems.
 
RFSchaller said:
FWIW at the ROTAX course I took the instructor said messing with the factory setting on the mixture was a frequent cause of business for him to straighten out an owner's tinkering. Not saying you can't adjust it, but you may be causing yourself more problems.
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It's not about tinkering, it's about not being set correctly from the factory. Factory setting is one and a half turns from the full in position.:p
 
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