I'd say that it shouldn't matter. The distinction wasn't really a big deal until cars started being built with catalytic converters. AV gas doesn't have the additives necessary for it to work correctly with the catalytic converters. Gas sold for use in cars/trucks does. But you don't have a catalytic converter soooo..... why would that matter?

If you are buying the 100LL "Blue" AV Gas you are essentially getting old skool "low-lead" 100 octane gas. If you are buying UL91 or UL94 you're buying unleaded 91 or 94 octane...

 

I've been running av gas (100LL) in all my small gas engines, two & four cycle, for at least ten years. No problems. Get them out in the spring and they fire right up. I know it's more expensive but I don't use 3 gallon a year and the airport is very close by.

 

Are you guys seeing a significantly better shelf life?

 

Av Gas (100LL) has to have a guaranteed shelf life of at least 2 years without any treatment - its primary function is use in aircrafts which have a much lower tolerance for fuel problems and tend to sit longer durations.

A few additional notes:

• 100LL is now almost always generally 100VLL i.e. 100 octane, Very Low Lead
• The amount of lead in AV Gas now (VLL) is pretty close to zero due to the lead not being as important with modern aircraft engines having hardened valve seats
• Leaded fuel will ruin catalytic converters
• I personally use AV Gas on all my small 4 stroke engines and have had zero problems as a result of it (I use the Stihl moto-mix on my 2strokes because its easy and I rarely go through a gallon a year.
• My snowblower (11HP I think) started on one pull after over 18 months of storage with a full tank of AV Gas.
• I always store my single cylinder pull start engines on the "compression" stroke to keep the intake & Exhaust valves closed.
• Its reasonable to assume that burning a leaded fuel will have fumes that may be more harmful than an Ethanol based fuel. (Breathing any exhaust isn't good, leaded might be worse.)
• Not all airports will sell it/allow it to be pumped in small containers.

 

I mix the av gas 50/50 with non oxy from the pump. I use it in all my 2 strokes, garden tractors and antique tractors. Excellent shelf life, no more spring carb problems. I also like to throw an oz of marvels mystery oil in when I remember to!

 

I`ve gotta ask why ? The manual for my x739 states to use 87 octane with stabilizer for extended storage periods which is likely considerably cheaper . Higher octane is not necessarily better .

 

Ethanol fuel is trash that attracts water. I don't use AV Gas because of the octane. (and higher octane ratings don't equal more power, just a higher resistance to detonation) I use it because it better protects the fuel systems, I don't have to add a stability agent and it works. Before I had my 1025R I had a L130 on a 1/5 the property I have now. I was at the local airport on a weekly basis when I lived there so it wasn't inconvenient to get the fuel. Now my tractor is diesel, and my AV GAS/Small engine use is really limited to my generator (Sits for very long times, needs to be reliable) my snowblower (basically obsolete with my plow and sits for years at a time), and my pressure washer, used 3-4 times a year.. The 100% reliability of AV GAS for these is (To me) absolutely worth the cost/inconvenience of getting av gas (I'm no longer at the airport weekly, or even annually).

 

Hey Matt , I can understand the generator scenario but per the manual our tractors are good for a 10% blend by design , coming from the auto world (Ford ) higher octane generates drivability issues with lower compression ratios and unless you have a buddy at the airport a drain on the pocket . If I had a 426 Hemi in the driveway would be a different story . I would think the compression of these engines would react similarly but maybe I am out to lunch

 

I'm not telling you have to use x. Just stating what I'm doing. As far as compression/octane- sure higher octane is generally better served in higher compression engines, however, to counter that point the Lycoming IO-360 is a 180HP N/A aircraft engine (Piper Archer) and has a 8.5/1 compression ratio.

Edit: I'll add, if the Ethanol fuel is a good option, why do they limit it to 10%? Finding non-ethanol fuel isn't easy anymore- so its not like the engineers have much of a choice.

 

Higher octane is cooler running, but most av gas is low lead as far as I know. It’s probably fine, but there’s another reason to not run it in enclosed spaces.

 

In limited testing I have found 10% ethanol gives 10-15% less fuel economy and the shelf life is essentially zero.

There isn’t one good reason for it to be in anything we run.

 

Matt - ethanol is not limited to 10% , E85 is very common for high performance applications . Not really trying to canvas for flex fuels but trying to understand from the original post why to install AV fuel in a system designed for flex or reg fuel and what the advantage is considering the increased cost .

 

but trying to understand from the original post why to install AV fuel in a system designed for flex or reg fuel and what the advantage is considering the increased cost .

AV Gas is reliable, doesn't attract water and has an effectively unlimited storage time. Ethanol attracts water, breaks down in a relatively short period of time and left sitting, ruins carbs. Those are the advantages. The disadvantages are cost and convenience of obtaining fuel.

One could say the convenience of knowing that at the beginning of the mowing season (or anytime you haven't use a small engine in a while) you're not rebuilding/replacing a carb, or draining a quart of water out of a fuel tank are completely justification for the increase in cost.

Note: Performance is not an advantage or disadvantage, were discussing small engines for lawn care.

 

rydplrs - one good reason to run it is it burns cleaner with less harmful emissions - E85 gives 10-15% reduction in mileage - 10% ethanol is minor drop in most cases if set up properly . I like to think it also supports the farmers .

 

10% less emissions, but your using 10% more fuel, it’s a net zero.

I could go on about the additional energy’s used to create it also.

Add onto it the energy used to create equipment that gets scrapped because of ethanol damage.

If you really look into it it really is a scam. You can believe it or not, I’m done with this thread because it’s not something I really want to spend going over. Ethanol only looks kind of good if you use blinders any only look at details and not the whole picture.

 

I like to use ethanol free gas in my small engines, it's available locally but honestly I haven't had any problems starting my equipment with regular gas even after sitting over winter.

 

The power/mileage conversation is a whole nother topic. I do farm and I absolutely hate ethanol. Buying ethanol does not support the farmers, it supports big oil. If you do not believe me just look into how many ethanol plants are owned and operated by big oil and the amount of subsidies they receive. The original question I believe was av gas in small engines. I run 50/50 av gas and non oxy gas in all of my small engines, mowers, garden tractors and antique tractors. I do not do it because it performs that much better. People who use these fuels in the type of engines we are talking about do so because of the shelf life and the lack of ethanol. Ethanol eats certain rubbers and other materials typically found in older equipment. It also has sh** for shelf life and in allot of cases if left in equipment over winter months will cause harm and damage. Yes it costs more but the headache of dealing with the problems ethanol causes in fuel systems that get parked for extended periods of time is well worth it. I will run ethanol gas in a couple of my engines and mowers that get run throughout the summer but by late summer I burn it out and switch back to the mix. I feel like the ethanol battle for those who have not delt with it or had problems because of it have just not done their research yet or had to deal with the problems that it causes. To each their own.

 

in northern WI we seen to have a shelf life issue with our ethanol blended, and even premium 92 octane-no ethanol. Both of these seem to only last 3-4 months before going bad. You cant even get one storage cycle- spring to fall or fall to spring.

Several years ago on all my small engines I went to 100LL AV Gas, The only think I have heard is you could in theory have lead build up in the exhaust. I don't run enough through the engines to be an issue. but the shelf life has been considerably betty, and in my region AV gas is only about $.50 a gallon more. Also if you like to sniff the exhaust there is a higher protentional of having lead in your system. I am betting there is many other things we do the have a greater change of adding lead to your system.

Also some airports have MO Gas 87 octane, which is unleaded, but is supposed to have the same shelf life as 100LL

 

It's really very simple. Here are the negatives of using AV gas in effectively "lawn mowers" (or any non Aviation use);

1. It cost more per gallon
2. The engine really doesn't need the higher octane and doesn't benefit from it based upon how the engine is designed. But it also doesn't hurt anything, either.

Here are the positives;

1. Engine runs cooler which is a plus for any engine other than a diesel in the winter months.
2. Fuel doesn't degrade from the day you buy it.
3. Shelf life is excellent as blended
4. Doesn't need any "stabilizers" or "Anti Rot" blends to counter the ethanol in modern fuel
5. Fuel systems stay much cleaner as does the entire combustion chamber
6. No road taxes on the fuel
7. The "authorities" don't want you to use it for non "approved purposes", which is reason enough for me to use it.
8. The fuel is very stable and predictable, which is why it's used in aircraft.

We used to run AV gas in our street race cars. (Yes, I street raced, but never carelessly or recklessly and we always closed a rural road to race on it to keep the risk much lower. Yes, we were all young and "high Spirited") As the octane level gets above 100, it takes special accommodations of the engine to benefit from and utilize the fuel such as higher compression ratios, etc. When the octane level gets above 110, its really a specialized engine build or the fuel can / will diminish performance.

Why don't more people run this in non Aviation uses? Because of how its sold and where its available and frankly most people don't even think about it as an option.

Ethanol sucks as a fuel and its terrible on fuel system components, not to mention its terrible as a power source fuel. It's better than walking, but if you use it long enough in anything which isn't run on at least a weekly basis, you can almost guarantee that ethanol will leave you walking.......to the repair station...........

Ethanol's best feature is it guarantees my buddy with the small engine repair shop, about 1,000 machines a year with ethanol damage to repair. Amazingly, probably 80% of the 1,000 machines are the same ones if not every year, then every other year. My friend tells them about using non ethanol fuel and everyone is always going to do it, then next year they will be back once again for a new carb or other fuel system work. The best part is many of the customers bring in their mowers in the spring and their snow blowers in the fall, year after year.........

For those who want to go ahead and burn ethanol, the repair shops thank you and frankly, their economic future largely depends upon you continuing the same behavior, which looks like a pretty solid likelihood. The biggest threat to small engine repairs from ethanol are the new series of battery powered tools. Those are very likely to transform the small engine repair and service market over the next 10 years.

 

7. The "authorities" don't want you to use it for non "approved purposes", which is reason enough for me to use it.

HUGE selling point right there!!

 

I'm with Sulley on a specialized engine build over 110 octane. When I raced, mostly on the drag strip, we thought about AV gas, but I was running "stock" class and many engine mods weren't allowed. Also, reading through this post, I'm seeing "100ll" AV gas. Back in my day, early '70's, we called AV gas "115/145" meaning octane was at least 115 and not more than 145. Also at that time Sunoco had either 103 or 107 octane "Hi-Test" ! And ethanol gas was called gasahol and you paid MORE for that than real gas! AH, the good ol' days! Bob

 

Rydplrs is spot on. Sadly, so very much of what is reported and believed to be environmentally friendly is just the opposite. Ethanol is the poster child for this econut misconception. Utilizing ethanol consumes 65% more fossil fuel than it saves! This conclusion comes from a study conducted by UC-Berkeley. You'd be hard pressed to find a more liberal university, but yet this was their conclusion.

 

Good post as usual @SulleyBear

I really liked #7.

BTW, a few Winters back I helped out in the chainsaw shop. Worked for nothing in order to learn more about chainsaws. Roughly half the hand held equipment that came in for fuel related problems, all being ethanol.

Ethanol has never been about energy policy, it is pure and simple bribes paid to politicians.

 

Good post as usual @SulleyBear

I really liked #7.

BTW, a few Winters back I helped out in the chainsaw shop. Worked for nothing in order to learn more about chainsaws. Roughly half the hand held equipment that came in for fuel related problems, all being ethanol.

Ethanol has never been about energy policy, it is pure and simple bribes paid to politicians.

Thanks for the compliment and kind words, I do appreciate it.

At my buddies shop, they order many of the common carbs in dozen quantities as it's not cost effective for many of the machines to attempt to repair the damage of the ethanol on the carbs verses simply changing them out. And the small engines which sit the most between use are always the ones which have trouble.

For many chainsaw owners who aren't in the firewood business and use their saws on an as needed basis, I always tell them to buy either the quarts or gallons of TruFuel or an equivalent. Some do, but most always "Yea, yea, yea.....I am not going to spend $20 for a gallon of gas" as they are paying my buddies $88 per hour labor rate..................

Funny thing is, the really good fuel makes a pronounced difference in the performance of most saws. I was out cutting wood with a friend who is a Cardiologist. He was one of those who told me "I can't see paying $20 for a gallon of gas". Of course, he ran out of his gas while we were cutting, so I filled his saw with the Tru Fuel. Instantly it made a believer out of him. He couldn't believe how much better his saw ran and how much more power the good fuel produced.

The reality is the good battery tools are starting to catch on and for most users, really make sense. They are the biggest threat to the constant repair stream of engines with bad fuel which keeps 4 techs busy at my buddies shop.....

 

And just as there is gasbuddy for looking up current gas prices. there's 100LL for looking up Avgas and Jet A:

100LL - Aviation Fuel Prices

 

I'm either doing something right, or someone is watching over me, or I'm just plain lucky...don't know!

I've been using "regular" (84 octane??) for all my fuel needs and back in the 60's the pumps stated 'May contain MTB'...whatever that was! My engines ran so I didn't care!

I bought my first L&G, a 314, in '82 as well as a log splitter and filled them both with "regular". I used the 314 for mowing in the summer and clearing snow in the winter so it always had fresh gas and constant use I used the splitter the first fall and then it sat 'til early summer when I was ready to split again. After pulling on the splitter for 20 minutes, I pulled the carb bowl, cleaned out some "gunk" in it, and it fired right up. The splitter sat for few months and the same issue, wouldn't start. I was talking with my Cousin and he said, 'Put some StaBil in your gas.' With nothing to loose, I tried it and never pulled the bowl again on the splitter! I've also NEVER had a fuel related problem with my L&G's either...except once when I left it out in a driving rain storm and ended up draining 1/2 +/- gal of pure water out of the tank! I "lost" my 314 in a divorce in 2010 but the guy that got it turned the key, it fired right up, and he loaded it and drove away... that's 18 years on ethanol gas WITH StaBil.

I'm not saying that ethanol fuel is good, but with additional additives it WILL work and not destroy the fuel system in the process! Just my hand on experience. Bob

 

This is getting off the AV gas discussion, but since it has been broached, this is a good watch. BTW, I like this guy.