Need a fuel expert

[fields_mj]

I can and do buy Rec90 locally and it has no ethanol. If that were not the case, I'd be removing the ethanol with water. Between the saws, splitter, and other small engines I run about 10 to 15 gal per year with only about 5 of that being 2 cycle mix. If my tank is almost empty, I'll run it dry, but I'm not interested in trying to roll my 27 ton splitter over so I can drain the gas tank

 

[Jonny Quest]

There are some good ethanol stabilizers that can help. I've used LUCAS Safeguard Ethanol Fuel Conditioner with good results. Other options such as Star Brite, Ethanol Shield, Sta-Bil, etc. The other advice previously mentioned is good to consider: 1) small batches of pre-mix; and 2) not allowing fuel to sit in a carb for more than a week should alleviate most of your ethanol problems.

Remember that ethanol is hydrophilic and hygroscopic, so if you live / work in high-humidity environments, you need to be more vigilant with ethanol fuels.

JQ

 

[2StrokeFondler]

Well you can use proper equipment, called a separatory funnel. They are several hundred $USD for a 5-L. Kontes used to have the best prices on glassware.

View attachment 1080992

I always liked chemists hardware. So shiny

Octane will be ?

Lower.

Would you like a detailed experimental?

Sure, why not? Would be interesting to see, if a saw starts knocking with gas where the ethanol was removed.

 

[davidwyby]

Here in a hot dry environment the gas evaps quickly and leaves gum and dries out diaphragms. I used to run e gas and then drain, run dry, refill with bottled, run a bit, store. Big pain…now I travel a little to get e free…and store my saws and gas in a shed under 80°f

 

[sliceoflife]

What qualifies as leaving a saw sitting with a tank full of gas? 1 week? 1 month? 3 months? Where do we run into problems?

 

[muddy42]

What qualifies as leaving a saw sitting with a tank full of gas? 1 week? 1 month? 3 months? Where do we run into problems?

My basic understanding is that the problems with ethanol in two stroke engines are twofold
1. ethanol is a better solvent than gas and dissolves/eats into rubber, plastics in fuel lines and carb diaphragms.
2. ethanol attracts and latches onto water which sits at the bottom of the tank and causes running problems.
Plus modern gas just isn't that good and breaks down, goes stale and smells horrible. I find my motorbike runs much worse with less power on 3 month old fuel than fresh fuel.

How long? Addressing the numbers above:
1. this effect happens every time you leave fuel in the carb / fuel lines. Ideally run the saw empty after use, but certainly if leaving for a week. Modern saws say the components can cope with ethanol and ultimately the parts can be replaced.
2. As above, you want to run the saw dry so the fuel tank will be empty.
3. I try to use unmixed gas within a month. Less if it is mixed with two stroke oil.

A further approach is pre-mixed alkylate fuel, which lasts a lot longer and is kinder on machinery. It is expensive, but you can compromise and use it for the last tank of the day or in machines you use rarely etc.

 

[Tomos770]

Here in a hot dry environment the gas evaps quickly and leaves gum and dries out diaphragms. I used to run e gas and then drain, run dry, refill with bottled, run a bit, store. Big pain…now I travel a little to get e free…and store my saws and gas in a shed under 80°f

 

[muddy42]

its impossible to get e free in some places in the world.

 

[turkeybob]

its impossible to get e free in some places in the world.

I see you're in the UK muddy42? In case you didn't already know, depending on what part of the uk you're in, you can use Esso 99 supreme, it's 'e' free and a could fuel, stores well and equipment runs well on it. Available south of Stoke - on -Trent, right down to Avonmouth area, not NW or NE or SW. It is produced at the refinery in Southampton and 'e' free, the pumps show 5% but it is worded 'up to 5%, (this satisfies the green) but it's 100% ethanol free.

 

[turkeybob]

Should have wrote 'good ' not 'could' fuel!

 

[muddy42]

I see you're in the UK muddy42? In case you didn't already know, depending on what part of the uk you're in, you can use Esso 99 supreme, it's 'e' free and a could fuel, stores well and equipment runs well on it. Available south of Stoke - on -Trent, right down to Avonmouth area, not NW or NE or SW. It is produced at the refinery in Southampton and 'e' free, the pumps show 5% but it is worded 'up to 5%, (this satisfies the green) but it's 100% ethanol free.

Thanks. Yes I am aware of that. I live outside of that area but I take a few petrol cans with me if I do drive South.

 

[HansFranz]

LOL, how many organic chemists does it take to pull ethanol out of gasohol?

The process is only slightly less sophisticated than making a cup of Nescafe.

 

[davidwyby]

What qualifies as leaving a saw sitting with a tank full of gas? 1 week? 1 month? 3 months? Where do we run into problems?

Here in a 120* summer in a metal shed...days. Gas really starts to evap at 80. I insulated my little shop and put a mini split in it and keep it 80 or less 12/7. No problems since. Some saws have sat a couple months, maybe a little more.

@Tomos770 brilliant! Thanks! I will use it for long term.

 

[sliceoflife]

So in a basement that stays under 60F constantly... I could reasonably expect gas to be fine for a few months?

 

[davidwyby]

So in a basement that stays under 60F constantly... I could reasonably expect gas to be fine for a few months?

in that climate you'd have to worry about the eth soaking up moisture I think.

 

[TheTone]

If I could not get non-ethanol gas, I would pour any remaining ethanol fuel in the saw into a collection can to go into the car. Then I would run the saw dry and pull it over on choke a couple of times. The real problem with ethanol gas is leaving it in the carb and fuel line for extended periods. This is also true with 4-stroke engines with a carburetor bowl. The ethanol collects water causing rust formation and gummy crud in the bowl. With 2-stroke diaphragm carbs, the oil in the mixture will keep the diaphragms from drying out between uses. If you're worried about it, pour a small amount of pre-mix into the dry tank and crank it into the carb as is often done for long term storage.

 

[sliceoflife]

Found a public airport/airfield near me that sells eth free... like 5 mins away (closest gas station that has it is like 1 hr away)... assumed they only sell to planes, but emailed them and within a few minutes they responded that they're happy to fill a can for me if I walk up with one. Need to pick up a new gas can that I'll keep as my "ethanol free" can, then I can turn my current can into my 2-cycle mixing can.

 

[OM617YOTA]

Ethanol free really is the ticket, worth going out of your way to find.

I just rotated through my stored generator gasoline. Ethanol free, double dose of Stabil, stored in air tight 5 gallon NATO cans. Two years old, still ran perfectly in the generator, pressure washer, car, and truck.

It's area dependant, but I know from experience that around here, ethanol
gas would smell and run noticeably different in six months. A buddy has 15 gallons of three year old ethanol gas; it's leached red color out of his plastic gas cans and smells awful. Not sure what to do with it, nobody dares run it in anything they care about, even in tiny doses. If I had a cheap mower that would be easy to free up a stuck intake valve on, I might try it.

 

[Tomos770]

If I could not get non-ethanol gas, I would pour any remaining ethanol fuel in the saw into a collection can to go into the car. Then I would run the saw dry and pull it over on choke a couple of times. The real problem with ethanol gas is leaving it in the carb and fuel line for extended periods. This is also true with 4-stroke engines with a carburetor bowl. The ethanol collects water causing rust formation and gummy crud in the bowl. With 2-stroke diaphragm carbs, the oil in the mixture will keep the diaphragms from drying out between uses. If you're worried about it, pour a small amount of pre-mix into the dry tank and crank it into the carb as is often done for long term storage.

 

[stihltech]

I think a lot of the problems are less in a closed, full, non venting container. Ethanol or not. Even the canned fuels have longer life in that type of container, not in the saw.
90 days seems to be the magic number IN THE UNIT. After that you may start buying parts.
Glass jar diagnosis is still the best in a shop.