carbs and ethanol

deej · #1 09-28-2011, 02:10 PM

Several months ago there were discussions about using mogas contaminated with 10% ethanol and how to "ethanol-proof" the fuel system of the plane.

Did anyone ever determine if the carburator was compatible with ethanol, or if there were a way to make it compatible?

Thanks,

-Dj

krw5927 · #2 09-29-2011, 09:47 AM

I may have been a party to that discussion. I'm trying to do the same thing.

As far as the carb, I'm certainly no expert, but I believe the floats (especially the blue plastic-epoxy ones) are fine with ethanol. The only thing I'm really concerned with is the seals, which depending on their material make-up may or may not be ethanol tolerant.

Any carb experts out there that can weigh in on the seals/floats/etc in a Marvel carb (mine's MA4-SPA) and what sort of exposure to fuel they have, and what material they might be made of?

bkilby · #3 09-29-2011, 09:55 AM

There are some threads on here with some findings after some investigation.. in short, I think it was determined that mechanical fuel pumps (edit: not carb gaskets) are not compatible with ethanol (who knows how long it takes for it to be an issue). I think there was one company (Kelly Aerospace maybe) that was in middle of working on some compatible gaskets.

lostpilot28 · #4 09-29-2011, 10:19 AM

I could be wrong about this, but I thought the weak link in your standard-built RV fuel system was the mechanical fuel pump. Everything else, from what I recall, is OK with Ethanol.

mburch · #5 09-29-2011, 01:09 PM

Seems like carbs and ethanol are the only things I have to look forward to anymore...

mcb ...sorry for the off topic post, couldn't resist

turbo · #6 09-29-2011, 02:37 PM

there are many rvers using ethanol mogas. the price difference has never been higher. $2 plus.

deej · #7 09-29-2011, 02:39 PM

Quote:

Originally Posted by turbo

there are many rvers using ethanol mogas. the price difference has never been higher. $2 plus.

The ones I am aware of are using fuel injected engines. Anyone using a carb with ethanol mogas that can give us a PIREP?

-Dj

turbo · #8 09-29-2011, 04:04 PM

do some searches on this. lots of info. been mixn 100LL and reg gas for a long time with carb engine. probably saved the price of an engine overhaul. closing in on 4,000 hrs.

deej · #9 09-29-2011, 06:51 PM

Quote:

Originally Posted by turbo

do some searches on this. lots of info. been mixn 100LL and reg gas for a long time with carb engine. probably saved the price of an engine overhaul. closing in on 4,000 hrs.

Hi Ed,
Like I mentioned, all I found is people with fuel injection reporting usage with mogas.

Can you tell us what, if anything, you did to your plane to make it compatible with ethanol? How many hours have you been using the ethanol contaminated mogas?

Locally 87 octane is $3.62 and 100LL is $6.08, so I have a strong incentive to be able to use it, but I want to make sure I do it right and it is safe.

Thanks,

-Dj

turbo · #10 09-30-2011, 06:39 AM

i dont run straight car gas. 50/50 mix in right tank for take off and landing, 5/1 mix in left tank for cruise. MMoil as directed. been doing this for about 8 years.