Information regarding the use of Mogas containing ethanol

Current Jabiru engines use a Bing Carburettor which is ethanol-safe – in earlier engines I believe the carby floats and some seals etc were not suitable for use with Ethanol.  I’m not sure when this change occurred but I believe they do an upgrade kit for people who want to use ethanol.  Regarding the rest of the engine, we have not done formal testing (endurance runs etc) however we have a lot of informal reports of people using ethanol with no trouble.  There are some guidance notes about on using Ethanol in planes and generally the things to worry about are vinegarisation (oxidation) / moisture absorption / damage to components (corrosion or chemical attack).

In many important respects – things like how it burns, valve guide wear and detonation protection Ethanol is a good thing and is generally accepted to be better in these aspects than standard MOGAS.  Ethanol is actually commonly used as an octane booster to prevent detonation.  The drawbacks are mainly the operational ones I’ve noted above.  Unfortunately, they are quite significant for aircraft users. 

A bigger issue than the engine is the airframe – older Jabiru fuel tanks and fuel lines are not suitable for Ethanol and will need to be re-treated or replaced to use you’re your local dealer has information on what is required.

I’m not aware of any compatibility issues with the mechanical fuel pump and Ethanol but we have not looked at it specifically.  We have quite a large number of operators in countries like Brazil which have been using high-ethanol fuel for some time with no issues that I am aware of.

Regards,

Doug Smith

Engineer, Jabiru Aircraft