Originally Posted by AHicks

To prove a point, I would love a chance to be there while you try to tell one can of 1 year old mixed fuel, from another that's a day old, by flying it in your plane. Not going to happen. Not when messing with the average RC gas engine with a 6.5:1 compression ratio (or thereabouts).

What amazes me is that people think that because an engine is expensive, that it automatically demands premium, high octane or the freshest fuel available. Our fanciest engines are no pickier than a leaf blower....

Bottom line, do what you need to do if it makes you sleep well. Just don't condemn the rest of us for how we're doing things. There's a few of us with many (many!) years of actual first hand experience that we're basing our calls on.

I agree. For instance my 2 stroke jetski at the beginning of a new season. I had a full tank when I stored the watercraft with fuel stabil. Only. It is oil injected. It was in there at least a year. Since I didn't want to mix old fuel with new I spent a day at the lake beating on it till the last drop. That 2 stroker with a head mod and tuned pipe ran like a raped ape all day. I still could pull from my buddy on his ski and he had new fuel. That engine had no issue running 7000 RPM at 65mph for hours. The next weekend I filled it up with new fuel. It ran exactly the same.

Originally Posted by AHicks

To prove a point, I would love a chance to be there while you try to tell one can of 1 year old mixed fuel, from another that's a day old, by flying it in your plane. Not going to happen. Not when messing with the average RC gas engine with a 6.5:1 compression ratio (or thereabouts).

What amazes me is that people think that because an engine is expensive, that it automatically demands premium, high octane or the freshest fuel available. Our fanciest engines are no pickier than a leaf blower....

Bottom line, do what you need to do if it makes you sleep well. Just don't condemn the rest of us for how we're doing things. There's a few of us with many (many!) years of actual first hand experience that we're basing our calls on.

I didn't say anything about these engines requiring high octane fuel. Ethanol is the contributing factor to fuel degradation, and unfortunately 87 octane has not been available ethanol free for quite some time. Pretty much the only way to obtain ethanol free fuel from a pump is to buy premium. I'm not buying premium for the octane level.

I would gladly take your challenge with one of my engines that I know like the back of my hand.

And you are correct about most rc engines being no pickier than a leaf blower, but there is one big difference... nobody gives a crap about their leaf blower. The only time they do is when it doesn't run.

I'm not condemning anyone to anything, people are free to do anything they want to do. And believe it or not, I have a few years of experience that I am basing my calls on as well. It's not unusual for me personally to clean and rebuild upwards of 50 carbs per week in spring time. Chainsaws, leaf blowers, weed eaters, generators, construction equipment, and on and on and on. No pickier than an airplane engine, but they sat all winter and won't start. Step number 1, drain old gas...

I fly airplanes for fun and relaxation. A few extra dollars is worth it to me to avoid any potential headaches in the spring time. I understand many others don't have a problem with gas that sat all winter and that's great. It's not worth chancing it to me with the little free time I have. I want to fly when I'm at the field, not fix. Fresh gas is just a little extra insurance that I personally feel is worth it.

• Premium fuel is as likely to contain 10% ethanol as any other grade.
• Ethanol has a much higher octane rating than pure gasoline, and is used to help boost octane rating.
• At an automotive gas station, unless the fuel is labeled as having no ethanol, it contains ethanol.
  • Eric, if you are buying premium that is not labeled as ethanol free, it almost certainly contains 10% ethanol.
• Outdoor garden equipment (and motor vehicles stored long term) have suffered from gasoline degradation over the winter months long before ethanol use was mainstream at 10% in most fuels.
• Yes, ethanol attracts moisture, which can induce rust in steel fuel tanks or steel lines, but it's not the sole reason gasoline degrades in performance and gums up carbs over time.
• 1 oz of Stabil per 2 gallons of gas really helps.

Where I live ethanol free gas is available at some stations but I've seen it offered only in 87 octane.

Of course I'm buying premium fuel labeled as ethanol free... that's the whole idea. It's also at a gas station who still uses separate lines for each grade of fuel rather than 1 line for all grades of fuel. Unfortunately in my area, buying premium fuel is the only way to get ethanol free.

The moisture that ethanol attracts can wreak havoc in an aluminum carb, I'm not sure why some believe aluminum is unlikely to corrode? It doesn't just affect steel alone.

Since the dawn of miniature aviation fuel quality has perplexed modelerkind. Why not run known good/fresh fuel and concentrate on flying the next wild 3D stunt your trying to learn instead of yelling out "Hey, did that engine just quit????".
I live in Minnesota, so 6 months flying and 6 months no flying making it a simple call at least for me and the recycling place takes old gas if you don't have lawn mover or any other gas burner that doesn't leave the ground.
I found the product pictured when the last issue about dated fuel came up and fuel properly stored can stay useable for some time, to address other input.

Originally Posted by Eric_04

Being a small engine mechanic... I dumped any mixed up gas I had left over last fall once I put my gas powered planes up for the season. Whats a half a gallon or so of premium mixed with Redline cost?? A few bucks? Not worth any sort of headaches in spring time to me. I deal with bad gas and plugged up carbs daily, not interested in having to pull any of my carbs apart on my planes if I dont have to.

4-5 month old gas (even with a stabilizer) will absolutely not behave like fresh gas. It still blows my mind some people will spend thousands on a plane, but they refuse to toss $4 worth of old gas that is most likely going to cause reduced performance.

I don't know where these other guys are coming from, but this is definitely my experience in Texas. Old ethanol gas is bad news. I took apart a pressure washer this week that wouldn't start. It had a plastic screen filter on a fitting that inserted into the gas tank. It was so clogged with this purple sticky slime that no fuel could escape. The nasty smell of that gas fouled my garage for days.

I had an almost brand new lawn mower I pulled out in the driveway to sell. I hadn't started in months, and it sure wasn't going to start now, while I waited on a buyer to arrive. I opened the drain on the carb bowl, and it took me a while to comprehend what came out. Pure water. Water! A lot of it! Maybe it's more of a problem in humid Houston and coastal areas, but Ethanol soaks up the water, and it separates. The foul part that's still left as some sort of Frankenstein petroleum byproduct gums up everything.

I've got a boat and four pieces of gas lawn mower equipment and the pressure washer. I've had headaches with all of them over and over due to this bad gas. Just this weekend, I flew a plane I hadn't flown in a few months. It's an almost new engine. First flight, it was fine. Second flight, it bogged and died as I went to take off and wouldn't start well or idle until we took apart the carb and cleaned out all the passages with carb cleaner. Believe me, I had better things to do on that sunny spring day than spending half the day fighting a perfectly good engine fouled with that damn ethanol gas.

I was looking at a manual for my lawn mower this weekend. It's got it right there with all the warnings. Don't use gas that's more than 30 days old. They're not kidding. Definitely don't dump it in your car's gas tank either!

Many years ago I was taught ...... "the nose knows" when it comes to good or bad gas. If the odor is off, don't use it. If it still smells fresh, good to go. It is also a good idea to look in the gas jug to see if there is any separation of either oil or water.

I'm not a great supporter of using ethanol gas in our engines but there have been many cases of problems and separation when using non-ethanol gas. Simply put gas has different formulations all over the country ....and I'm talking the base gas before any ethanol it mixed with it. Oil has been known to separate and form balls in some gas formulas when it sets over time. The dreaded "clear slime" that can cover and clog screens was discovered well before ethanol gas was common and yes, the problem still exists.

I got a bad batch of non-ethanol premium gas early last season that caused me to have to rebuild several carbs and tanks. It literally dissolved some fuel lines and rubber parts. I switched to a different source (from a different pipeline from the refiners) and the problem went away. I've noted the premium gas I buy in Northern Minnesota (from Northern refiners) is more stable than what I buy here in Iowa that comes from the Houston area and Oklahoma refiners.

I use my ethanol free gas from the fall in the spring. I have had no trouble. I even leave a tank full in all my planes, so the first tank is always old fuel. Never an issue. If you are using ethanol fuel, that is a different story, but treated fuel is good for a year no problem.

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Originally Posted by AHicks

To prove a point, I would love a chance to be there while you try to tell one can of 1 year old mixed fuel, from another that's a day old, by flying it in your plane. Not going to happen. Not when messing with the average RC gas engine with a 6.5:1 compression ratio (or thereabouts).

What amazes me is that people think that because an engine is expensive, that it automatically demands premium, high octane or the freshest fuel available. Our fanciest engines are no pickier than a leaf blower....

Bottom line, do what you need to do if it makes you sleep well. Just don't condemn the rest of us for how we're doing things. There's a few of us with many (many!) years of actual first hand experience that we're basing our calls on.

+1

A lot of the Heli gas guys use Coleman fuel in their engines... that’s 55 octane... and it runs as well as pump gas. Just expensive.


So many folks WAAAY overthink this. I just mix 32:1 and run it in everything. The extra oil won’t hurt anything, actually it helps. I’ve run 6 month old gas and can’t tell the difference. When it gets really old I’ll dump it in the lawnmower.

I have used old gas many times. I have had to clean/rebuild carbs on model engines and a hedge trimmer, but I attribute it to not running the engine dry and leaving fuel in it over a winter. After several seasons of making sure I empty tanks and run engines dry, I can not really tell old fuel from new.

If you are really concerned about the ethanol in gas, try using:

pure-gas.org

it is a website for non ethanol gas suppliers. A lot are marinas. The one in downtown Cincinnati is a tool rental company and it sells 91 octane. it was about $2/gallon ABOVE local regular gas prices the last time I looked.

Several years ago I considered using aviation gas. There is an airport about 2 miles from my home that sells 100 octane ethanol free aviation gas at about the same price I am paying for premium gas at the pump. When I read through the manual for my DA Engine I noticed they said the warranty would be void if aviation gas was used. I decided not to use it but I am curious as to why they do not want it used in their engines. It does contain lead and maybe that is a factor.
Just for the record I use 93 octane premium E 10 gas with 40 to1 redline oil. I fly as much as I can during the winter months but if I have gas that is a few months old I take it to the hazardous waste collection.

Originally Posted by Colton

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That is a shame, but I completely understand your reasoning for deleting your post. Not worth the headache.