Thread: MoGas use

I have read a lot here about pilots using auto gasoline (I am assuming 92 octane) and the problems with lead build up from 100LL. This is a real newby question but, can you mix MoGas and 100LL? My guess from reading is that guys use MoGas at home and then 100LL on the road. Does it effect the performance is can you not tell the difference?I have never used auto gas in a plane so this is all new to me.

Thanks

Mixing is OK. I doubt that you can tell the difference in performance. You might want to keep a log of how much fuel you use and what percentage is 100LL for maintenance records. Tom

I use MoGas (Sunoco 93 octane, with ethanol) at home and 100LL when traveling. I've never detected any difference in performance.

The preferred fuel for Rotax 912ULS is unleaded fuel with 91 octane or better and not more than 10% ethanol (none is best). I do not have ethanol-free premium fuel available in my area. While several places locally sell ethanol-free 87 octane for use by boaters, nobody has it at octane levels of 91+. While there are a number of airports that do sell ethanol-free MoGas, every one that I have checked with only had it with octane levels lower than 91 since it is typically sold to traditionally certified aircraft with a MoGas STC, and I think most of those only require 80 octane.

When using 100LL with the Rotax, you have to do more frequent oil changes to prevent damage from lead deposits. Some people use an additive like Decalin, but I have not used it since I haven't been able to track down any specific approval for it.

When using MoGas with ethanol, you have to be much more vigilant about water in the fuel. Also, for SLSAs, both the engine and airframe manufacturers must approve use of ethanol fuel because it can be incompatible with some fuel system components like tanks, fuel lines, etc. For example, in my CTLS, the fuel filter had to be replaced in order to be approved for fuel with ethanol. Also, fuel with ethanol should not be allowed to sit in the tanks too long between flights.

Originally Posted by Pawlander

When using 100LL with the Rotax, you have to do more frequent oil changes to prevent damage from lead deposits. Some people use an additive like Decalin, but I have not used it since I haven't been able to track down any specific approval for it.

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Randy,,have a look at paraprah 5.2) of the following


http://legacy.rotax-owner.com/SI_TB_...-016&S_TYPE=MS

Rotax don't specifically recommend it but they say ''Other similar additives are not advised...."

Thanks, Jacques. I was aware of that wording, and would be okay using it as far as the Rotax is concerned. Unfortunately, as far as I know, Flight Design hasn't weighed in on whether it is okay for the fuel tanks, lines, etc.