Has Anyone Had Issues using Shell Auto Gas?

[MrMorden]

Point taken.. Unless there has been a recent change, Rotax only allows E10 (10%) in their aircraft engines. My early serial number Remos GX is not designed for ethanol - incompatable with the fuel system, only allowed in later models. The 40 million hours flown cited by Rotax is primarily in the Pretator running AVGAS FYI...

I could be mistaken, FD might only allow 10%...I know that they were working with Rotax to *test* 15%, but I don't know what the results of that were. I do know some folks in SA are running 22% though...talk about crap gas!

[drdehave]

More to my tale... After the wierd fuel-pressue hiccup using the Shell gasoline, I went back to Chevron, but to a new station I had not bought from before. I put 10 gallons in the airplane.

Next morning, I did my normal sump-drain of a pint or so, and hold the jar up to the sun light. What TH? There's what looks like a white "worm"--maybe 3/8" x 1/2" long--in the bottom of the jar!
I swirl the jar in a circular motion and wha-la, the 'worm' dissolves and dissappears into solution! I hold the jar still for 10 seconds and wha-la, the worm coaggulates & reappears!

Some "Techtron" additive that a man or machine dumped too much of into the fuel? I don't know, but I'm starting to side with the thought, stated above, that one of the problems of Mogas for aviation uses is poor quality control--at least compared to Av-gas.

I think I'll just start buying premium Mogas from the Circle K store near my house, and stop driving all over town trying to hedge my bets....for best quality. Around here, it's all coming from one of two refineries.

Rich

[CharlieTango]

Rich,

are you sure that you are not seeing phase separation?

[drdehave]

"are you sure that you are not seeing phase separation?"

Well, it sure didn't look like anything in the dozens of pictures of gasoline with phase separation you get by Googling "gasoline phase separtion."

And, drawing more from the sump, neither that day, nor each of the next three, with the same air temperature and humidity, produced the same kind of funniness.

[FastEddieB]

There's what looks like a white "worm"--maybe 3/8" x 1/2" long--in the bottom of the jar!
I swirl the jar in a circular motion and wha-la, the 'worm' dissolves and dissappears into solution! I hold the jar still for 10 seconds and wha-la, the worm coaggulates & reappears!

Rich

Are we 100% sure there's no Tequila involve in this incident???

[cogito]

More to my tale... After the wierd fuel-pressue hiccup using the Shell gasoline, I went back to Chevron, but to a new station I had not bought from before. I put 10 gallons in the airplane.

Next morning, I did my normal sump-drain of a pint or so, and hold the jar up to the sun light. What TH? There's what looks like a white "worm"--maybe 3/8" x 1/2" long--in the bottom of the jar!
I swirl the jar in a circular motion and wha-la, the 'worm' dissolves and dissappears into solution! I hold the jar still for 10 seconds and wha-la, the worm coaggulates & reappears!

Some "Techtron" additive that a man or machine dumped too much of into the fuel? I don't know, but I'm starting to side with the thought, stated above, that one of the problems of Mogas for aviation uses is poor quality control--at least compared to Av-gas.

I think I'll just start buying premium Mogas from the Circle K store near my house, and stop driving all over town trying to hedge my bets....for best quality. Around here, it's all coming from one of two refineries.

Rich

Are you sure the "worm" isn't a fiber from the fiberglass tanks on the Sting Sport?

http://www.eaa.org/lightplaneworld/arti ... arning.asp

-Craig

[snaproll]

More to my tale... After the wierd fuel-pressue hiccup using the Shell gasoline, I went back to Chevron, but to a new station I had not bought from before. I put 10 gallons in the airplane.

Next morning, I did my normal sump-drain of a pint or so, and hold the jar up to the sun light. What TH? There's what looks like a white "worm"--maybe 3/8" x 1/2" long--in the bottom of the jar!
I swirl the jar in a circular motion and wha-la, the 'worm' dissolves and dissappears into solution! I hold the jar still for 10 seconds and wha-la, the worm coaggulates & reappears!

Some "Techtron" additive that a man or machine dumped too much of into the fuel? I don't know, but I'm starting to side with the thought, stated above, that one of the problems of Mogas for aviation uses is poor quality control--at least compared to Av-gas.

I think I'll just start buying premium Mogas from the Circle K store near my house, and stop driving all over town trying to hedge my bets....for best quality. Around here, it's all coming from one of two refineries.

Rich

Are you sure the "worm" isn't a fiber from the fiberglass tanks on the Sting Sport?

http://www.eaa.org/lightplaneworld/arti ... arning.asp

-Craig

Craig,
Or dissolved resin - I still suggest you look into the test to determine how much ethanol is in the fuel.
I am in southern California, routinely climb to 9,000 ft on the ol' $100.00 hamburger trips, and cannot afford phased separation, vapor lock, etc. My tank is not compatible with ethanol, resins will slowly dissolve, etc. I will continue running 100LL until there is a suitable source for 91 Unleaded without ethanol.
I recently retired from decades of managing three military fuel operations (three bases) including aviation and ground fuels. My lab stayed busy daily running samples for quality control and conformance with standards. I routinely sent samples to a Class 1 lab for in-depth analysis. The usual findings on mogas were variations in the ethanol content ranging from 8 to 20 percent – and all receipts were from major refineries that supplied commercial gas stations. Vapor pressure and octane variations were also a problem. As previously mentioned, quality control is a major problem with commercial automotive gasoline. You may receive 91 octane one day and 89 the next. Being the curious aviator I am, I also sent samples of 100LL from the local airports to the lab – an average of 25% failed to meet specifications. Go figure…
VR.. Don

[Jack Tyler]

"I recently retired from decades of managing three military fuel operations (three bases) including aviation and ground fuels. My lab stayed busy daily running samples for quality control and conformance with standards. I routinely sent samples to a Class 1 lab for in-depth analysis. The usual findings on mogas were variations in the ethanol content ranging from 8 to 20 percent – and all receipts were from major refineries that supplied commercial gas stations. Vapor pressure and octane variations were also a problem. As previously mentioned, quality control is a major problem with commercial automotive gasoline. You may receive 91 octane one day and 89 the next."

Don, it strikes me that you are offering a unique, relevant (and lab-based, no less) perspective on what we would all like to take for granted as consistent, quality-controlled fuel (both aviation & ground vehicle). Please expand your comments a bit: What conclusions and actions did you take, if any, when you found the high variability in fuel quality? Did you discontinue buying fuel from a given refinery, or discontinue buying a specific blend the refinery produced, or discontinue buying from a given distributor? Or did the contracts permit this kind of variability? And did you find the variability in fuel quality was inconsistent, by which I mean were some suppliers able to provide less variable, more consistent fuels while others were the source of the variability? I'm thinking of folks like Rich, who is trying to pick a supplier based on the quality of the fuel they have available. If you found variability in fuel characteristics across the board, then our hopes of finding the 'right supplier' may be wishful thinking.

FWIW my local rural airport is operated by an aviation authority that operates Jax International and buys lots of fuel for its four airports. I would think the (Chevron) distributor they use would make sure this customer gets consistently reliable fuel supplies. But our ramp staff always test the fuel on arrival and they will occasionally have to reject the fuel...which is then taken down to Keystone Municipal about 30 miles away, a fuel retailer known for the low fuel prices. (The airport manager told me this week that the authority is switching to a contract with a Shell distributor). Does make one think when a cross-country flight finds us fueling at a distant FBO about which we know very little of the 'inside story'.

[MrMorden]

It would also be interesting to address what the fuel suppliers say about this kind of variability... Is it an "unacceptable" level of variance, or is it "within industry norms for fuel"? It seems if that is the expected level of change from one batch to the next, then our engines are designed around that and our fuel requirements are set to take that into account. If not, well...then not.

[snaproll]

"I recently retired from decades of managing three military fuel operations (three bases) including aviation and ground fuels. My lab stayed busy daily running samples for quality control and conformance with standards. I routinely sent samples to a Class 1 lab for in-depth analysis. The usual findings on mogas were variations in the ethanol content ranging from 8 to 20 percent – and all receipts were from major refineries that supplied commercial gas stations. Vapor pressure and octane variations were also a problem. As previously mentioned, quality control is a major problem with commercial automotive gasoline. You may receive 91 octane one day and 89 the next."

Don, it strikes me that you are offering a unique, relevant (and lab-based, no less) perspective on what we would all like to take for granted as consistent, quality-controlled fuel (both aviation & ground vehicle). Please expand your comments a bit: What conclusions and actions did you take, if any, when you found the high variability in fuel quality? Did you discontinue buying fuel from a given refinery, or discontinue buying a specific blend the refinery produced, or discontinue buying from a given distributor? Or did the contracts permit this kind of variability? And did you find the variability in fuel quality was inconsistent, by which I mean were some suppliers able to provide less variable, more consistent fuels while others were the source of the variability? I'm thinking of folks like Rich, who is trying to pick a supplier based on the quality of the fuel they have available. If you found variability in fuel characteristics across the board, then our hopes of finding the 'right supplier' may be wishful thinking.

FWIW my local rural airport is operated by an aviation authority that operates Jax International and buys lots of fuel for its four airports. I would think the (Chevron) distributor they use would make sure this customer gets consistently reliable fuel supplies. But our ramp staff always test the fuel on arrival and they will occasionally have to reject the fuel...which is then taken down to Keystone Municipal about 30 miles away, a fuel retailer known for the low fuel prices. (The airport manager told me this week that the authority is switching to a contract with a Shell distributor). Does make one think when a cross-country flight finds us fueling at a distant FBO about which we know very little of the 'inside story'.

Jack,
I would be difficult to provide a fuels education online due to the technical complexity but there are a few actions that can be taken by anyone. First, the ethanol content of mogas can be a killer, as you never know what you are actually receiving unless you test it. Commercial gas stations seldom “low point drain” their tanks to remove excess water and contaminates from their tanks. With the ethanol blends being sold, the water is picked up by the ethanol and absorbed. Additionally, the underground tanks are seldom cleaned, seldom inspected, and the dispensing equipment has not been upgraded for compatibility with ethanol.
Sources are emerging for unleaded 91-octane fuel without ethanol. In the west, Cleargas (http://www.cleargas.co/) has emerged and is expanding distribution for aircraft and marine use. Many of the smaller refineries will sell 91 octane fuel without ethanol in bulk once an airport or marina sets up a tank to receive it. There is no source in my area yet but several airports are considering it. The ideal cure for the Rotax powered and auto fuel STC’d aircraft is fuel without ethanol. Auto fuel was doing well in aircraft prior to the ethanol introduction, the result of the MTBE ban. Ethanol is a strong solvent and is corrosive. Many of the folks I know are now replacing aluminum fuel tanks destroyed by mogas with ethanol, i.e.. Filled with mogas, sat for too long, separated, and resulted in high concentrations of ethanol on bare aluminum. The dollars saved at the pumps have been overcome by the increased maintenance cost.
Lab testing and receipts – Non-spec deliveries were rejected. The non-conforming deliveries did not point to one or two refineries or brands. Of the AVGAS I had tested, I can only say that the Chevron product never failed to meet spec.
I think the bottom line is you must be proactive and make sure you are receiving a good product, safe to run in your airplane, and not compromise your safety in the air. EAA has published numerous papers on ethanol containing fuel, has provided safety guidance, and is the best source for information.
Lastly, there is one additional issue with high concentrations of ethanol – fires. Ethanol will continue to burn under AFFF. Ethanol requires AR-AFFF for firefighting (AR = alcohol resistant).

[roger lee]

If it runs in your car or motorcycle it shouldn't be an issue for the Rotax.

[MrMorden]

If it runs in your car or motorcycle it shouldn't be an issue for the Rotax.

Even if the octane drops below 91, on a hot day in a hard climb?

[snaproll]

If it runs in your car or motorcycle it shouldn't be an issue for the Rotax.

Even if the octane drops below 91, on a hot day in a hard climb?

Sorry, but I miss the old days when your choices in AVGAS were red, blue, or green.... Most cars and older airplanes only require 87 octane. Current production cars adjust both mixture and timing based on combustion effectiveness - not so with Rotax. When Rotax says 91 octane - they mean 91 octane or above. Again - EAA has an abundance of information available.
VR.. Don

[Jack Tyler]

Thanks for the further comments, Don. And yes, I think a/c owners are in wide agreement - here and more generally - that any given mogas source (Circle K, regional like Gate, or company store owned by one of the majors) means accepting the unknown. I know many pilots now feel that avgas (100LL) has grown too expensive to support recreational aviation. But it does usually come with performance and quality benefits moreso than most mogas.

"If it runs in your car or motorcycle it shouldn't be an issue for the Rotax."

Sorry Roger, but that's the kind of generalization that hides lots of variables. Don's reply illustrates just some of them. I sure do wish things were that simple.

[dstclair]

Being the curious aviator I am, I also sent samples of 100LL from the local airports to the lab – an average of 25% failed to meet specifications. Go figure

But it does usually come with performance and quality benefits moreso than most mogas.

Jack, I don't think the former statement supports your conclusion.

Seems to me Don's analysis says all fuel varies from its standard and neither 100LL or MoGas is better than the other.