Question about gas oil mix

RN1204

Hello. My name is Greg and I am located in North Louisiana. This is a nice forum. I am and outdoorsman, tree lover, and nature fanatic. A warm hello to all.

I do have a question. I recently purchased a Stihl 391 (New). I have used my father's chainsaw on a limited basis in the past. I now have my own obviously.
Today, I thought of something that alarmed me. I am on my Third tank of fuel and have been cutting with it the last couple of weeks. I filled my fuel tank last week with one gallon of 89 octane gas + 1 bottle of STIHL 2-cycle oil to make the 50:1 ratio. Oil in can first with gas pumped to mix it.
What I did not think of on the second and third saw refueling (first was filled by dealer) was to shake my gas can before refueling. I cannot believe this did not cross my mind. It was a dumb move on my part.
What I would like to know is this: How quickly does the oil settle out of the fuel, and in an experienced opinion, have I prematurely worn my engine due to too lean of a mix because of not shaking my fuel can? The saw has not gotten hot that I can tell and there is black residue around the muffler outlet. I have not seen it smoke heavily with used though. I was told by a family member that some high quality two-stroke oils are smokeless???
I sincerely hope that I have no damaged my saw. This makes me sick to even think of that. Ultimately, I should have been thoughtful enough to shake the gas container. I just hope my new investment is not accelerated in wear

glennak

Stihl oil should not settle so don't worry about it. Most new 2 stroke oils have a surfactant added (so I heard somewhere) so the oil is suspended. Same as the detergent they put in milk to homoginise it so the cream will not float.
I still give the fuel can a shake now and again just in case but really not necessary.

dov

I always shake the fuel can just in case, but have never noticed the oil separating. One bloke I used to work for didn't shake his fuel can except when mixing and his saws ran ok.

bipot

First of all, your gas in Louisiana has ethanol added which can separate out over a little time and cause your carburetor to run lean on you if used that way. Second, quit using 89 octane and moveup to a minimum 92 octane. Add stabilizer to it to keep it fresh. As well, you may want to switch to a good synthetic oil. There are many threads in this forum and others to read about the ethanol problem. Do a google search and read about that. Windthrown and others on this site have discussed this topic in much more detail. Check your Stihl manual and stick to the minimum octane rating.

windthrown

I would suggest getting the lowest % of ethanol and highest octane that you can for your chainsaws. I go to Washington state to get better super gas; gas in Oregon is all 10% ethanol, Washington is more like 4%. Also add gas stabilizer as soon as you fill your gas cans. That stuff will keep the octane high but it cannot restore lost octane due to evaporation of the lighter fuels in the gas mix. Gas drops in octane pretty fast, and drops more when you add premix oil to it. Products like StaBil will keep gas fresh for a year or longer. It will also keep the ethanol from phase separating with any water that gets into the gas.

As for mixing the gas and oil, 2-stroke oil is pretty thin, and any agitation from filling saws is usually enough to mix it well enough. I have never had a problem with oil phase separation in 2-stroke mixed gas myself. I buy super gas and store it in 3-5 gallon cans, and mix it with oil (45:1) into 1 gallon plastic cans for using in my saws and blowers. As said by others above, use a good 100% synthetic 2-stroke oil. I use 100% synthetic low smoke Elf FC/FD that I get at a local motorcycle shop. Look on the labels. Do NOT use TWC outboard motor 2-stroke or all purpose premix oils. Use only oils designed for air cooled 2-stroke engines. They are far fewer, so you have to hunt them down. Meaning do not buy cheap 2-stroke oil at the local Stop-N-Rob store.

The muffler oil residue is typical of FB or lower rated 2-stroke oil. That stuff smokes a lot, and fouls engines and mufflers and muffler screens pretty fast. Flip to JASO FC or FD oil and the smoke and residue problem will go away. The exhaust will also smell better and the gas mix will be cleaner burning. I run a slightly richer oil mix to improve ring seating in my saws. Old school moto-cross dirt biker here. 50:1 will run just fine with any good oil and gas out there though in just about any modern chainsaw. I tune my saws to my gas mix; more oil in the premix will make it run slightly leaner (meaning you need to turn the H screw to run a tad richer with a higher oil ratio). Also note that summer gas is different than winter gas in the US. Winter gas blends are usually more volatile, and summer blends are less volatile.

dov

Man you guys seem to have pretty bad fuel in the States. Where I am the standard petrol has an octane rating of 91 and no ethanol. You can get ethanol fuel here, but it's not popular. Further north in Queensland or Northern NSW it's more popular because of the Sugar Cane lobby. Where I am however, it's not so popular and vendors have to put warning labels on the fuel bowsers clearly marking how much ethanol is in the fuel and that it may affect fuel economy. Won't touch the stuff myself...

windthrown

Until last year all gas in this state was pure gas (unusual in the US at that time). Then Oregon decided to be a leader in crappy gas to 'save the planet and become energy independant', and mandated that all gas here be 10% ethanol. At that time it all went to shit. Marine engines have been the most affected, and those guys dump StaBil in boat gas by the ton (and still have huge issues with water getting sucked into the gas by the ethanol). It is so bad and they got so many complaints (the state legislature) that they allowed non-ethanol supreme gas to be sold here again starting this year. However, I have yet to find any non-ethanol gas actually for sale in this state. StaBil responded by coming out with their green formula for treating ethanol gas in marine engines.

Gasoline in the US is all formulated differently by state law, so there is huge variation in gas here by state (basically 50 different blends). California had MTBE in their gas for a long time. That stuff stank. It was found that MTBE leaked into ground water, and runs for miles in underground plumes. So the US government banned it. That forced California to reformulate their gas with ethanol. Generally in the early days, gas was 'oxygenated' with ethanol and MTBE and other products to reduce air pollution in the larger cities, especially in winter months. For oxygenating, ethanol at a rate of 4-5% is about the optimum for reducing smog and retaining fuel efficiency. However, Oregon wants to be a leader in stupidity, saving the world and favoring the ethanol/corn lobby, and requires that we pay more (gas is taxed at both the state and federal level) for crappier gas with lower efficiency and power, as well as pay for all the ethanol related problems in engines and gas tanks, carberators and fuel injectors.

Of course, we pay about half what they do for gas in Europe. And for some reason we like to dump crude oil into the Gulf Of Mexico by the ton (more stupidity there than you can shake your fist at). The economy is tanking again, so the price of oil has been going down pretty fast leately. Contrary to that, the price of gas here is going up because of the holidays (summer gas gouging season in the US).

glennak

I had never heard of MTBE so I looked it up 2-Methoxy-2-methylpropane is its IUPAC name. I don't think it's in our petrol. I run my wifes car on an ethanol mix as I decided it was a cleaner way to raise the octane rating of petrol (gas) I always thought they should have used ethanol instead of Tetra Methyl Lead. After your comments widthrown I will not run it in my chainsaws. I haven't in the past but thats just because the stations I fill up at don't sell ethanol mix. The only problem I can see with cars is that if the car was left without driving the fuel may take up water from the air, or am I missing something?
As for your ethanol from corn in the US that is totally stupid using food to run cars. The energy put in to grow the crop harvest then distil must exceed the energy from burning the stuff. Better use

bipot

The corn farmers here in the US are ecstatic about the refiners using it to generate the ethanol. First, they easily sell their crops for that purpose and what little does go to the grocery store, demands higher prices to purchase an "ear of corn".

windthrown

Yes, legislatures are wooed by the energy independance claims of burning corn, and in reality it uses more oil to generate ethanol in the end (many studies show this, as first described by a professor at Cornell University). Also burning corn drives the price of food up as well. Its a shell game, and lots and lots of lobby money pours into well greased palms to lubricate the political engines of America. Its really weird at the crop growing/farm level, where they could not get farmers to grow corn at all last year. Seed was selling for dirt and no one planted it. If this economic crisis pans out like the one in the 1930s, the prices of commodities will crash as well, including farm crops. We shall see. Oil should be about $40 a barrel, but speculation drives prices to insane levels.

Using ethanol as an oxygenate (4-5%) makes sence to reduce smog, but past that there is no sence in burning it, other than in warm places like Brazil that until recently had no known major oil reserves. They make sugar cane into ethanol gas down there. Most high ethanol (E-85) blends here in the US have been a failure marketing wise. Ethanol does funny things at low temperatures in the northern US states in winter months, and is not practical for using at higher levels than 85%. The energy available in ethanol is only 60% of that of gas, so paying gasoline type prices for E-85 (or even E-10) blended gas seems insane from an economical perspective. About like buying hybrid cars which cost so much more than conventional engine technology that gas would have to be two times the current price just to break even, even with the current tax rebates. But driving a hybrid is trendy, and you get to use the commuter lanes on the freeways with them, driving alone. That kind of defeats the purpose of commuter lanes, but that in itself is an insane idea. At the height of commute hours, reduce the number of available lanes?

Energy use is all pretty insane, especially in North America. Obama talks a lot about alternative energy, but the fact remains that in the US, alternatives/renewables (not including hydro) only account for about 3% of the total energy produced and used. Energy corporations like BP talk a lot, but in reality their sloppy drilling methods have led to massive oil spills in the Gulf of Mexico. The only real hope near term is in conservation and better efficiency. We have been reducing our energy rate by about 1% a year per person in the US, while China is going in the opposite direction. Green energy is just becoming politicized, and things like ethanol and hybrids (and even hydrogen) are touted as the answers, when in fact they all just use energy at an even faster pace. The Greenies here refused to vote for Al Gore and as a result GW Bush was elected (even with a smaller total popular vote). So even at the so-called grass roots level, politics just fails miserably when it comes to energy. The future of humanity looks rather dire. 7 billion people demand a large amount of food and resources, never mind global warming (human/CO2 caused or not) and other economical and ecological disasters.