I was preflighting my 601 this evening and when I took a fuel sample, the valve started leaking badly. I snapped the valve which reduced the leak to just dripping. Turns out that the o-ring is not auto fuel safe. Anybody know of a replacement o-ring that can withstand mogas?
Tags:
I went with McMaster but it looks like Grainger is cheaper. It is a -006 and I used Viton. The o-ring first saw mogas last August so failed in less than a year. I don't know what the 7 series models, or, for that matter, what the 650s use but the CAV-110 valves from Aircraft Spruce use an o-ring that is not automotive fuel safe.
You should note that in a review on Aircraft Spruce, so others don't fall into the same trap.
Doug that is odd, I’ve been using three of those Saf-Air CAV-110 valves for four years now with no problems and all I use is regular grade ethanol-free car pump gas. Did Saf-Air change O-ring suppliers?
Update: I drained the tank last night and removed the valve. The o-ring looks fine but there was a bit of debris on the sealing surface so I believe that was the issue, not the o-ring. I am getting the Viton rings in today so I will swap out the rings anyway. One more thing - I use 93 octane mogas with ethanol. I can't get 93 ethanol free gas around here and the Jabiru 3300 calls for 93 minimum.
Zenith Planes & Parts For Sale
Classified listings for buying or selling Zenith builds and parts...
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:
Flying On Your Own Wings:
A Complete Guide to Understanding Light Airplane Design, by Chris Heintz
Transition training:
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.
© 2026 Created by Zenith.Aero.
Powered by
Exlusive online community for active builders and pilots of Zenith Aircraft kits (Chris Heintz / Zenair light airplane designs).