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  #1  
Old 01-21-2019, 07:56 PM
dabney dabney is offline
 
Join Date: Feb 2008
Location: valencia, ca
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Default RV12 Rotax 912 Occasional Erratic EGT indications

The engine has 100 hours on it. On the FlightDEK D 180 the EGT L and R consistently run about 1250-1260 usually within about 10 of each other. Without any change in the throttle EGT L will rise to 2000 for a for 5-10 seconds which of course sets off the alarm for high EGT. Then they return to the previous "normal" indication.

Can't think of an explanation for this myself, any ideas for troubleshooting or prior experience with similar problem?
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  #2  
Old 01-21-2019, 08:28 PM
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Piper J3 Piper J3 is offline
 
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Possible wiring connector needs cleaning or EGT thermocouple is bad. I had both issues. Replaced thermocouple at ~ 100TT.

EGT, Hose Clamp, 0.75-1.25", Rotax SKU: #100405-001 $46.89. Bought directly from Dynon in 2016
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Last edited by Piper J3 : 01-21-2019 at 08:34 PM. Reason: Added EGT purchase info
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Old 01-22-2019, 08:15 PM
RFSchaller RFSchaller is offline
 
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Location: Phoenix, AZ
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Iím on my third EGT probe at 816 hr TTAF. The first one failed at about 260 hours. Second was a faulty replacement part that was bad from the day I put it in. The third has over 650 hours on it. The right EGT has never been replaced.

Before you buy a replacement swap leads in the engine compartment and verify the issue swaps with the probe.
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Old 01-23-2019, 07:43 AM
JBPILOT JBPILOT is offline
 
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Location: Jesup, Iowa
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Default Just for note - -

I recently replaced my first one at over 1,100 hours. I did have connection issues a couple time thru the years.
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  #5  
Old 01-27-2019, 03:03 PM
Charlie12 Charlie12 is offline
 
Join Date: Oct 2014
Location: Port Orange FL
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Default loose connector?

I started having occasional erratic temp indications on my left EGT at about 70 hours. Re-crimping the wire connectors up near the firewall penetration fixed it. At my next condition inspection I replaced the thermocouple because I didn't trust it, but it may be that I was being too cautious.
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Old 01-27-2019, 05:36 PM
AirHound AirHound is offline
 
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Other than hardware (sensor and connections) and software what can cause actual 912ULS EGTs to differ?
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Old 01-27-2019, 07:43 PM
RFSchaller RFSchaller is offline
 
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If one carburetor is running leaner than the other it would cause that side to run hotter since the balance tube doesnít do much at cruise RPM. But that wouldnít cause spiking.
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Old 01-27-2019, 07:55 PM
Azjulian Azjulian is offline
 
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Location: Scottsdale, Arizona
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I had this happen early on (20 ish hours) I re-crimped both prove leads and itís been solid since
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Old 01-27-2019, 09:38 PM
AirHound AirHound is offline
 
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Quote:
Originally Posted by RFSchaller View Post
If one carburetor is running leaner than the other it would cause that side to run hotter since the balance tube doesnít do much at cruise RPM. But that wouldnít cause spiking.
Rich, in general, is the only way to adjust mixture on our machines just at idle with the set screw ie; 2 vs 1.5 turns?

Otherwise, itís mostly about the internal environment/material condition of the Bings regarding mixture at cruise speeds?

I was under the impression that the balance tube was mainly effective at higher RPM?

Regards,
Doug
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