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George858
12-02-2008, 01:51 PM
I have a 2001 Kitfox 5 with a Rotax 912S -- My question is regarding Fuel.
Rotax says that that engine must use premimum fuel. The only premimum fuel we have in North Idaho contains 10% Ethanol ! and Rotax says to not use fuel with that much Ethanol in it. Also I do not know what that would do to my planes fuel system (tanks & Fuel lines) I have heard that tanks could leak and lines could become unuseable ?
The only other option I guess is 100LL which again Rotax does not like because they say it is bad for the engine valves, and the engine in general.
The only fuel we can get without Ethanol here is one station that has regular unleaded.
Can octane booster be used to raise the regular to an octane that compares to the preminum gas or is the need for premimum in the engine not really required ? and the non Ethanol regular could be used
I guess my question is what fuel should I use??
Thanks

RandyL
12-02-2008, 03:24 PM
I've talked to several operators of 912S who are running on premium auto fuel with the 10% ethanol in it and they all report no problems. Of course you'll want to make sure your fuel system hoses etc. are compatible.

I know several others also who run on a steady diet of 100LL and as long as you don't use full synthetic oil and keep your oil change intervals shorter they are reporting no other problems either.

Hopefully others will comment on their fuel choice and operating experiences.

DesertFox4
12-02-2008, 04:31 PM
100 % 100LL for me. Only tried premium auto fuel with alcohol once and had a bad experience with the fuel dissolving the resin in the wing tanks. This happened after only two tanks run through in about a weeks time. Fouled both carbs so bad the Rotax 912S wouldn't run. Full tear down of both carbs and intense cleaning and then rebuild kits to get them to work again. Almost broke down and bought two new carbs. Never again. I think the Rotax will tolerate it but my fuel system most definately won't.
Using 100LL is not a concern if you do it properly. Use Delcolin fuel additive from John at Kitfox Aircraft LLC. and change oil at 25 to 50 hours of service. My spark plugs have never fouled, ever. They get changed every 100 to 150 hours and come out perfect with a light brown color. The Delcolin works and you can safely carry it in your airplane. The other brand if it spills will melt your paint. Don't ask how I know this.:( I also use a little Marvel Mystrey Oil to help keep the hydraulic lifters from sticking in every other tank of fuel at about 5 ounces per tank. Seems to work with no ill effects.
Stay away from full synthetic engine oils when running 100LL. The new Shell oil that Kitfox Aircraft LLC. now carries looks like a good choice.

George858
12-02-2008, 05:03 PM
Thanks Steve for the reply
George

George858
12-02-2008, 05:04 PM
Thanks Randy

Skybolt
12-23-2008, 10:51 AM
The only other option I guess is 100LL which again Rotax does not like because they say it is bad for the engine valves, and the engine in general.



Hi George.
I agree with what DesertFox 4 is saying.
About the Shell oil (it even has Rotax on the label).
I also use the Delcolin fuel additive from John at Kitfox Aircraft LLC.

When I was using the super unleaded auto fuel I was getting fuel leaks from the sample valves. The stuff would soften the rubber rings.

When you think about it. With LSA getting popular for training and personal use, Rotax has sort of relaxed on the use of 100LL. They have to or they will not be selling engines for this segment.

Eric.

wadeg
01-27-2009, 12:54 AM
For ethanol-free auto fuel, try checking with your state marine board. Here in Oregon, the marine board lists on their website the sources of ethanol free fuel since a lot of boats have had trouble with ethanol.

Also, I buy my eth-free stuff at an oil company. Bought a 55 gallon transfer tank for my truck and just get it filled when I pass the oil company. They sell loads of the stuff for farm equipment and it's popular amongst the yard car folks with 2 strokes.

Furthermore, my truck loves the stuff when I'm too cheap just to go to the gas station and I want to use up "old gas" (at least that's how i justify it)....

Skybolt
01-28-2009, 09:12 AM
A friend of mine had to make a landing in a field (with his wife on board)
A Cessna 120, believed it clogged up the carb with stuff breaking loose in the fuel system. This airplane was approved for Autogas. Not the corn mash stuff that is now blended in. Kind of moonshine:>)

No one hurt. Wife scared out of here wits. Much damage to aircraft where it sliced through the fence and pot holes.

Eric.

dcy92444
02-02-2009, 08:59 PM
"Stay away from full synthetic engine oils when running 100LL. The new Shell oil that Kitfox Aircraft LLC. now carries looks like a good choice."

I was hoping that you might consider elaborating on this piece of information. I have a KFm 112 and run 100LL but recently switched from 15W50 Aero Shell to Amsoil 5W30. I have found my engine starts better, runs cooler with lower EGT and CHTs. I have heard this about synthetics before but I know that the Aero Shell is partly systentic. So what is the difference? Cold starts are much improved also. This is not a challenge but a request for help and information. Thanks

Dee

Mnflyer
02-03-2009, 08:31 AM
Hi Dee, the problem with full syn oils and 100LL is that full syn oils do not scavenge the lead and hold it in suspension as dino oils do thus over time the engine becomes lead fouled. This is why Mobile got sued and removed their Mobile 1 aviation from the market many years ago. And changing oil at shorter intervals is not the total answer as the syn oils just don't remove the lead in the first place thus the lead deposits its self in the crankshaft oil passages and will eventually clog the passages causing bearing failure.
As to why your engine starts easier syn oil flow much better at low temps causing less drag for cold starts, it would be far better to use an engine preheater and semi syn oils IMHO.

Dave S
02-03-2009, 02:25 PM
Hi folks,

One question that I have pondered; and still am not exactly sure of it this:

Full synthetic oil is the recommended oil for unleaded auto gas in the Rotax; and, a person cannot use full synthetic oil if leaded fuel is used, for the stated reasons. That all makes sense.

Now - what does a person do who burns mostly unleaded auto gas; but, may occasionally need to burn 100LL?

The rotax manual I have for the 912ULS says a person can run up to 25% leaded aviation fuel; but I don't remember seeing anything about what to do with the oil in this case.

In other words, is there anything wrong with running oil which is not fully synthetic all the time in the case that occasionally a person may end up using 100LL?

Sincerely,

Dave S
K7 Trigear
912ULS Warp

BTW - at least for Minnesota folks, or those who visit here, there is a listing of all gas stations which sell unleaded 92 octane auto gas. This is located on the Minnesota Street Rod Association website as a 4 page PDF. The site is www.msra.com - then click on "Features" and you will see a selection for "non-oxygenated fuel". The car folks have issues with ethanol too (not too many jokes about that now! Although, I will mention that one corn gas refinery in Benson, MN also makes a high octane Vodka on the side.):)

Mnflyer
02-03-2009, 06:11 PM
Hi Dave, personally I don't think occasional use will hurt anything much it takes a long time for the lead to build up, I use 100LL in my HKS occasionally, which has the same wording about 100LL and alcohol usage . One could carry a small bottle of Decalin runup in the plane and add it when fueling with 100LL or use the new Aeroshell oil developed for these type of engines. If we lose the non alcohol 91 Oct here in MN I'll go with 100LL, use Decalin and a semi syn oil but probably not the shell oil as its way overpriced in my book.

DesertFox4
02-03-2009, 09:42 PM
Dave - you may run non-synthetic oil exclusively as I do. I have used Honda's Pro motorcycle oil exclusively in both my Rotax 912 & 912S equipped Kitfoxs'. Make sure you use a high grade oil which meets Rotax requirements like Honda's Pro oil and that it has the gear case additive, like Honda's Pro oil. This gives you the protection you need for both engine and gearbox and the flexibility to use 100LL Av-gas if you need to. You should use Delcolin fuel additive if running predominately 100LL Av-gas. An occasional tank of 100LL AV-gas, like you might need to use on a cross country trip, should give you no concern at all. You are not damaging your engine.

RandyL
02-05-2009, 07:40 AM
"Stay away from full synthetic engine oils when running 100LL. The new Shell oil that Kitfox Aircraft LLC. now carries looks like a good choice."

I was hoping that you might consider elaborating on this piece of information. This is not a challenge but a request for help and information. Thanks

Dee
Dee,

They have found in testing that synthetics don't keep the lead that inevitably makes its way into the oil in suspension as a good detergent oil is supposed to. Rather it lets the lead deposit everywhere inside the engine. The inherent properties of petroleum oil by contrast do keep the lead from sticking and thus let it drain when you change your oil. Synthetic blends (aka "semisynthetic") provide the benefits of both and really are the proper solution for a Rotax run on 100LL. That's wy AeroShell just introduced such an oil. Mobil introduced a full synthetic into the aviation market some time ago and eventually had to take it off the market for this very reason. It is also why the two leading premium oils, Aeroshell 15w-50 and Exxon Elite 20w-50, are both semisynthetic.

As you know, because of the PSRU, motorcycle oils are a good match for the Rotax. Accordingly Honda oil has found favor with Rotax operators. They make two oils that are popular, GN4 is a conventional multi-vis petroleum, and HP4 is their semi-synthetic. Of course there are others.

paulc
02-10-2009, 02:52 AM
100LL vs Auto, My 2 cents!

100LL GOODIES

Avgas 100LL: Higher Octane ratings MON.100, RON120
Formulated for anti detonation due to high Tetra-ethyl lead content
Formulated for anti vapour locking at altitude
Formulated for anti valve, guides and seat wear due to Tetra-ethyl lead content
Formulated for high tolerance to mixture fluctuation i.e. anti fouling properties.
Does not run “summer” and “winter” blends
No Ethanol
Is manufactured with tight chemical tolerances i.e. batch consistency
Airport depots and pumps strictly check for water and other inclusions on a daily basis and sign off.
100LL BADS

More expensive
Not available every where
Lead not good for planet
Lead does not mix well with 100% synthetic oils


AUTO:GAS GOODIES:

Readily available
Cheaper than Avgas
Can be used with any oil
AUTO GAS BADS:

Not certified
Less tank inspections for inclusions
Low octane 85 MON, 98RON (lower number for non premium)
Detonates earlier due to low octane number and absence of Tetra-ethyl lead.
Vapour locks earlier due to formulation
Winter and Summer blends
Less tolerance to mixture fluctuation i.e. black carbon build.
Ethanol blends destroy many plastics and rubbers
No upper cylinder lubricants (nothing for valves, guides and seats) absence of Tetra-ethyl lead.

Learn more about octane and ratings here: http://en.wikipedia.org/wiki/Octane_rating (http://en.wikipedia.org/wiki/Octane_rating)

kitfox812
02-10-2009, 06:26 AM
George

I can still get non-ethanol fuel in
Bonners Ferry at the Exon/Pacific Pride Pump. Also the Co-op in Sandpoint. There may be more down your way for the boaters near Coeur D Alene. A couple of us here use AV-9 from California Power Systems. It is advertised as a 912/914 semi syn oil with additive and buying it in two case lots comes to about $6/qt with shipping.

Rich

mr bill
11-02-2011, 06:20 PM
State of Wisconsin exempts airports from requiring alcohol in the gas. Here is a list of known airports in Wi that have mogas with no alcohol. 02C, BUU, 57C, 62C, 88C, C77, C47, KHXF and KMTW. Most of them sell only premium and the prices range from $3.66 to 4.90. There are many others in Wi and IL. These are just the ones I know of.