Has Anybody Tried G100UL?

Hi Craig

If this is a certified you need an STC to use it unless approved by your OEM.  If experimental you're correct, nothing required.  When a fuel is not on the listing at Rotax simply means it has not received any testing that they have qualified as suitable.  I am not familiar with G100UL and have no data on it myself so it is perhaps a boutique fuel or regional fuel at best for your area.  

To be clear on the recommendations from Rotax.  Currently the latest SI, service information, on fluids has only 2 call outs.  50 hour for leaded fuels and 100 hour for unleaded.  They do suggest for activities such as flight training (lots of touch and go flights) a reduced time frame for oil changes due to excess build up in the system of contaminants especially for leaded fuels.  

Cheers

G100UL is the new fuel from GAMI.  I believe they made a big announcement at Oshkosh in 2021.

https://gami.com/g100ul/g100ul.php

Since it's 100 octane and in an experimental, you are going to be fine, and you'll be able to go with longer oil-change intervals.

As the Wizard points out, the official Rotax guidance is 100 hours between changes if using unleaded fuel.