in my engine which has burned 10% ethanol for years with no problems.
I understand that 15% ethanol is coming soon and will be death to outboard engines.
Accordingly, I want to switch to ethanol free; however, a friend cautioned me not to mix free with 10% blended-he could not tell me why this is a “No-no”?
“Watch what we do,not what we say.” John Mitchell
Sea Hunt Triton 202
Yammy 150
Sounds like BS to me, if you mix you may end up with 5% which is way better that 10%. If you can find it Id definley run Real gas. My yamaha manual says dont go psat 10%. Hmmmm a good way of getting out of warranty?
Yes, I agree, this sounds like BS to me too.
“Watch what we do,not what we say.” John Mitchell
Sea Hunt Triton 202
Yammy 150
It’s pretty much a non-issue any longer. At one time funky things could happen when mixing ethanol fuel with non-ethanol fuel containing MTBE, but MTBE is longer used. I’m not so sure it was the MTBE mix that caused the problems rather than the ethanol, but I’m not the one to ask. I never had a problem with anything ethanol … 
It is my understanding that MTBE was the problem but it is no longer used in gas. I have mixed them in my boat with no problems after having ethanol issues. I did try to run the gas low before making the switch just to get as much of the ethanol out as possible.