Autofuel

[Paul Misteli]

Hello

have anyone experience with autofuel in C170B with C-145-2 engine?

Kind regards

Paul
C170B HB-CYV

[bagarre]

Hi Paul,

There is an STC to run mogas in the 170 but finding ethanol free mogas is quite difficult these days.

The STC does not allow fuels that include ethanol.

The topic of running ethanol laced mogas has been passionately discussed here as well. If you did a quick search for Ethanol, you'll see what I mean Passions run high on both sides of the argument but in the and, wether it works or not, the FAA says it's a no no.

I'm sure someone will chime in with the actual STC number.

Hope this helps to some degree.

[Andy Metzka]

Both the EAA and Petersen have STC's for auto fuel. I have only run it for about 1400+ hours in a 120 and a 170.

Yes- you WILL find beliefs pro and con. My experience is no more plug fouling and lower operating costs. It is roughly 2 dollars a gallon cheaper than 100LL here. I DO feel you should NOT use it if your plane sits for extended periods of time-say more than a month or two- in which case you likely wouldn't save much anyway. I usually fly about 100 hours a year and never had any problems. Several of my friends also use it.

http://www.autofuelstc.com/

http://www.eaa.org/autofuel/

[GAHorn]

Paul, in the U.S. autofuel is very difficult to find which is not premixed with ethanol. In YOUR country, perhaps it is easier.

Although autofuel is cheaper, it is not as carefully regulated and formulated and may contain additives which are harmful to your aircraft fuel system seals, gaskets, O-rings and other components. It may cause expensive damage.

Autofuel does not have the durability for storage that aviation gasoline has either. Autogas deteriorates much more quickly than aviation gasoline.

It may also violate your aviation regulations and/or your insurance policy, so you might wish to look into that.

[hilltop170]

If you decide to use mogas and not sure if it has alcohol in it, just buy some water based food color such as Adams and put a few drops in a jar of mogas. If it has alcohol, the food color will dissolve, disappear, and color the gas. If no alcohol, the food color drops will go straight to the bottom and roll around the jar as you gently agitate it. Even if shaken vigorously and the food color breaks up into smaller drops, they will coalesce back into big drops in the bottom when you quit shaking it.

This is the best, easiest, most accurate, and cheapest (and most messy if you spill the food color) method I have found.

I would not hesitate to use mogas in a pinch but not long term any more, especially if not burned right away. Never store anything more than a month with mogas in it. I use 100LL in everything that does not have a catalytic converter, mowers, chain saws, dune buggy, motorcycles, tractors, classic cars, hot rods (especially 11:1 compression hot rods).

With the above being said, I ran leaded regular Texaco mogas in my C-170 and C-180 for 20+years and hundreds if not thousands of hours. I never had any problems related to the mogas. But now with the alcohol, I'm just not willing to take the chance of messing up my airplanes. Plus, I like the smell of 100LL.

[GAHorn]

http://pure-gas.org/ is a link to a site which purports to document gasoline retailers who sell non-ethanol gasoline throughout the U.S. I notice many of them are marine dealers. One of them (Keller, TX) is near the raceway in FTW and probably sells to sophisticated race drivers. They claim to have 112 octane but I don't know if that is one of their ethanol-free flavors. (They advertise 3 different octanes.)

This is no assurance that any of their fuels is suitable for aircraft use and I have no idea if they are compatible with aircraft systems materials.

(I can't believe I'm encouraging this behavior.)

[170C]

Although I have not purchased any due to not flying right now, locally in TN the Farmers CO-OP's carry regular unleaded auto fuel that does not have alcohol in it. Several of my friends here use it both in their planes and in small engines. Possibly co-ops in other areas might also have this product.

[cessna170bdriver]

I never figured out how to keep mogas from inundating the valve stems and rings with carbon. From what I've read, I'm one of the few people who had that problem. No problems whatsover with a diet of 100% 100LL since the mid-1990's.

[flyboy122]

Although autofuel is cheaper, it is not as carefully regulated and formulated and may contain additives which are harmful to your aircraft fuel system seals, gaskets, O-rings and other components. It may cause expensive damage.

.

This quote is dead on. (there is an intended pun in that statement) We ran auto gas for years and years, but then it started to become harder to find at local airports. I asked one FBO and he commented that they were no longer able to ensure the quality of the fuel so they stopped carrying it. Undeterred, I bought it at the local gas station, always sure to get the stuff labeled "ethanol free". Life was good until the engine quit on my PA-12.....in winter....over snow covered fields. Got it running and nursed it to an airport, but the real interesting part of the story was the postmortem. Both fuel lines had collapsed at the same time. If just one, or one and later the other, you could blame it on age or defect. But both within an hour of each other? (could tell by the amount of fuel in the tanks) Something in that load of fuel ate the lines.

Lotsa horror stories like that on the internet, and lotsa ways to justify it anyway. All I can say, from someone who has been there, done that, and lived to tell it about is that when you are trying to figure out which way the furrows are going under that snow, knowing that if you guess wrong it's REALLY going to hurt, well...all that money you saved buying car gas won't due you jack squat. You'd pay it back triple in a heartbeat if you could.

Odds are slim you'll get bad gas. They were slim I'd get it. So slim I'd run it again in a pinch if I were stuck somewhere. But play the odds long enough and you'll lose.

Today's car gas is just not the same as the gas they used for those STC's. Buck up for avgas and enjoy the ride.

DEM