Have spent some time chasing an erratic egt gremlin.  First indication was a noticeably lower egt than any other cylinder - chts looked normal.  After a few more flights the egt started out low and on climbout went very high (1400+).  Exhaust pipe inspection looked same as the others.  Previous egt issues were fixed with a new sensor - all good.  Went through 3 sensors, swapped leads, replaced entire egt wire/connectors to the pin in the DB25 (dynon ems/hdx).  Dynon did an outstanding job working with me the whole time.  Ultimately swapping a refurb ems to check the system.  No change - same lo/high indications.  Closer inspection revealed a break/crack in the sealant on the induction pipe from the carb manifold to the cylinder.  Removed, cleaned, reseated/sealed pipe with Jabiru recommended Loctite gasket sealer #2.  Check flight today - back to normal egts!!!  Lesson learned - ensure to closely inspect the induction pipe seal.  There is an O-ring in the manifold, but the seal can make a noticeable impact on the fuel/air mixture to the cylinder and the resulting egts.

Views: 136


Reply to This

Replies to This Discussion

Thanks for posting this, James. Stuff like this is very helpful to folks coming here looking for answers/clues.

Awesome post.   Thanks I will know to be watching for this.  

Thanks for posting this! I've been chasing the same issue on my Gen3 cyl 5 and 6.  Previously, I hadn't gone all the way back to the manifold to check for leaks. (didn't see any) Did this time, Took a deep breath today, pushed the throttle forward, and Tadaa! No more issues. Slowly working the bugs out of my recently purchased 601. And having fun doing it.   


New from Zenith:

Zenith Planes For Sale 

Classified listing for buying or selling your Zenith building or flying related stuff...

Custom Instrument Panels
for your Zenith

Custom instrument panels are now available directly from Zenith Aircraft Company exclusively for Zenith builders and owners. Pre-cut panel, Dynon and Garmin avionics, and more.

Zenith Homecoming Tee:

Zenair Floats

Flying On Your Own Wings:
A Complete Guide to Understanding Light Airplane Design, by Chris Heintz

Builder & Pilot Supplies:

Aircraft Insurance:


West Coast USA:

Pro Builder Assistance:


Transition training:

Lavion Aero

K&S Aviation Services

Aircraft Spruce & Specialty for all your building and pilot supplies!

How to videos from HomebuiltHELP.com

Developed specifically for Zenith builders (by a builder) these videos on DVD are a great help in building your own kit plane by providing practical hands-on construction information. Visit HomebuiltHelp.com for the latest DVD titles.

© 2024   Created by Zenith.Aero.   Powered by

Badges  |  Report an Issue  |  Terms of Service