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  • Re: Possible Vapor lock?

    by » 3 months ago


    I’m a bit at a loss, as last Sunday’s flight was with fresh fuel from a high-volume station, so definitely not winter blend now.  My first occurrence was definitely fuel related.  91 non ethanol during phase 1 testing in FEBRUARY!  Had no appreciation for winter vs. summer blend and had never heard of RVP back then.  Got educated really quickly after that.  Yes, I could add some 100LL, but hate to introduce the lead to the system, as conditions at this time don’t seen to warrant it.  But if it persists, I guess it will be my next step.  


  • Re: Possible Vapor lock?

    by » 3 months ago


    My fuel was a blend of 93E10 and 93E0 both from fresh sources and filled that same day. 

    With good fuel, is Heat and Altitude enough to cause these temporary drops in fuel pressure?

    I read some forum posts previously about the possibility of a clogged fuel filter downstream of the fuel pumps? Could a "beginning to clog" or partially clogged fuel filter shows symptoms like this, but only in extreme circumstances? like high heat and altitude?

     

    This is the very first instance for me, so I'm truly trying to figure out if something on my aircraft is degrading or if I need to be smarter than the environmental conditions I'm operating in, and just run 100LL blend.

     

    Thanks all or the replies so far!!


  • Re: Possible Vapor lock?

    by » 3 months ago


    We use E10 in Arizona with OAT's at  100F - 110F. Because the 912iS has such a high fuel return rate compared to the 912ULS I have never heard or seen any vapor lock issues with the 912iS.


    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell


  • Re: Possible Vapor lock?

    by » 3 months ago


    Wesley, let me give you a couple of other data points…. My fuel pumps were replaced about 20 hrs previously per Rotax’ recent SB.  I had completed the Rotax 200 hr maintenance and my annual condition inspection about 5 hours before my latest fuel pressure issue.  In the course of those activities I cleaned the coarse filter located before the pumps and replaced the Rotax fine filter located after the pumps.  So, I had ruled those out as contributors.  If our weather ever clears 🙂 I’m going to see if I can replicate the issue using current fuel before introducing the AVGAS factor.


  • Re: Possible Vapor lock?

    by » 3 months ago


    Yeah I replaced my fuel pumps per the SB as well. They showed improved fuel pressure from the very beginning as compared to the old pumps. But the old pumps never had to deal with this much heat.


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