?? About octane for mowers and chain saw

[nybirdman]

In NY state the non-ethanol is 91 Octane;I run in all my small motors.My Stihl equipment likes it for sure.The trick is non-ethanol not the octane rating.If I could get 87-89 non-ethanol I would use it.

 

[marchanna]

The good news for you in NS is that ALL your premium grade automotive gasoline has NO ethanol.
Same for PEI, and NB, I believe.

I don稚 know for sure. It痴 hard to get a straight answer. Compared to other regions I don稚 see any difference in my fuel economy.
Shell apparently uses petroleum-only in their V-Power Diesel and Gas.

 

[ericm979]

E10 is not really the cause of all small engine problems AND bad breath like what gets repeated on the internet. When it was introduced it did cause some fuel system problems in vehicles whose fuel systems were not designed for ethanol. But that was a long time ago (1980s here). All modern carbs, fuel lines etc. handle E10 just fine. Ethanol does make the mixture leaner (it takes about twice as much ethanol per unit of air to reach stoichiometric ratio as it does with gas). But that just means slightly larger carburetor jets, or a slight change to the adjustment on a saw's carb. Ethanol doesn't make gas go stale appreciably faster; pump gas has always gone stale in a few months, even before ethanol.

We can't get E0 for a reasonable price here. I've done fine with E10 in all my gas equipment. The secret is to use a good fuel stabilizer and run the gas out of the carb if its going to be sitting for a while. The generator doesn't get run for seven or eight months over the summer yet it starts up first pull every winter. I run the carb dry after every use. It's still on the original fuel lines after 20 years. If a saw is going to sit for a while I drain the tank and run the carb dry. Aircraft "low" lead has a lot more lead than old leaded pump gas. Sometimes it's so much it causes plug fouling on two strokes.

 

[pathunt]

I have Stihl chainsaw and several mowers. We use 91 octane non-ethanol in anything that matters. Quit using ethanol in 2003 when my mowers would not run. 2016 Grandson-in-law used 87 ethanol in new Briggs mower = DOA. Sorry for him, but told him my experience.

 

[buickanddeere]

I have a Stihl chainsaw and weed eater that the owners manual says to use 89 octane. I also have a John Deere mower that the manual says to use 87 octane. I have been purchasing non ethanol gas for each of these octanes at a cost of about $1 a gallon more. I have been using the non ethanol because I understand that it is much better for these Engines than using gas with ethanol in it.

Recently a new station started selling non ethanol but only in 90 octane. My question is would it be OK to use this 90 octane in my mower even though it only call for 87 octane or am I going to eventually encounter a problem with using this gas. Same question for the chainsaw, is it OK to use 90 octane when the manual calls for 89 Octane.

Thanks

Going higher won稚 damage anything , going lower or using old gas that has lost some octane will. Holes burn through two stroke pistons for a reason and it ain稚 a lack of lub oil. Just use 91 octane non ethanol and don稚 worry about it . If you can not afford the price difference between 87 and 91 , then it is time to change occupations .

 

[buickanddeere]

I really doubt that it was the octane rating that caused it. Thousands of chainsaws are run every day on 87 octane. It could have been a hundred other things, but just the octane seems really unlikely. 91 and 87 really aren't that much different.

87, 89 , 91 and 94 are a lot different . I tried them all in the GN and monitored at what boost level detonation would occur at . 87 octane would ping while while driving into a parking lot spot .

 

[buickanddeere]

Octane is the measure of ignition delay. The higher the octane, the more the fuel can be compressed before it ignites. For best performance and reliability, you should use the octane that the engine is designed for. Using too low and you will get pre-ignition (knock), using too high and you will have lost power (higher octane fuel actually has less energy in it). Contrary to what some believe, higher octane is not synonymous with better fuel.

Ethanol blended fuel can damage seals and gaskets on older equipment, and is generally less stable, but is not poorer quality or cheaper fuel. Ethanol also has lower energy content than petroleum-based gas: about 10% less. At 10% blend, there is about 1% less energy overall - hardly noticeable.

octane is a measure of what temperature the air/fuel mixture will auto ignite .

 

[buickanddeere]

E10 is not really the cause of all small engine problems AND bad breath like what gets repeated on the internet. When it was introduced it did cause some fuel system problems in vehicles whose fuel systems were not designed for ethanol. But that was a long time ago (1980s here). All modern carbs, fuel lines etc. handle E10 just fine. Ethanol does make the mixture leaner (it takes about twice as much ethanol per unit of air to reach stoichiometric ratio as it does with gas). But that just means slightly larger carburetor jets, or a slight change to the adjustment on a saw's carb. Ethanol doesn't make gas go stale appreciably faster; pump gas has always gone stale in a few months, even before ethanol.

We can't get E0 for a reasonable price here. I've done fine with E10 in all my gas equipment. The secret is to use a good fuel stabilizer and run the gas out of the carb if its going to be sitting for a while. The generator doesn't get run for seven or eight months over the summer yet it starts up first pull every winter. I run the carb dry after every use. It's still on the original fuel lines after 20 years. If a saw is going to sit for a while I drain the tank and run the carb dry. Aircraft "low" lead has a lot more lead than old leaded pump gas. Sometimes it's so much it causes plug fouling on two strokes.

Actually it is the other way around . Modern 100LL has much less lead than the 1970’s automotive regular pump gas .

 

[RandyT]

Several of the high performance saw companies use compression ratios around 10:1 or even higher in some saws, there for call for 89 or higher fuel.

 

[marchanna]

octane is a measure of what temperature the air/fuel mixture will auto ignite .

Technically, yes. But as a consequence of compression, not because engines are designed to run hotter. In similar fashion, Diesel engines are called compression ignition engines.