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Hi all,

I have been using 93 octane Shell in my small engines off and on for the last couple of years. Now I know that using fuel with a higher octane rating than required is a waste of money. The reason I started using it was that someone said that the premium fuel doesn't have ethenol in it and I felt it would be better for my mid 70's Bolens H14Xl and mid 80's Bolens 1600 Eliminator. I also always treat my fuel with Stabil (I am almost out and am going to try Startron next). Once in a while when premium got too expensive I would buy 87 octane and use it. I didn't notice any major drive ability issues when using 87 but it SEEMED like the engines ran smoother on 93. At the end of last summer I acquired a '92 John Deere 420 with a bad engine. Over the winter I rebuilt the engine and changed all the fluids filters and hoses. I also resealed the intake manifold and put on a new carb before firing it up for the first time. The engine ran great and I didn't even have to touch the carb. A couple of weeks ago I filled the tank on the 420 with 87 and noticed after turning off the deck the engine was surging! I adjusted the idle mixture screw all the way rich without removing the limit cap and the engine ran better but not as smooth as before. Once I used up all the 87 and put 93 back in it runs smooth again! Has anyone else experienced better performance using high octane fuel in their garden tractors?

Jason
 

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small engines run HOT, so while there tuned for 87 and they run fine on 87, they can run better on 93.. ~some~ 93 octane is ethanol free, but not all. If it is where you live, that would explain the lean issue your noticing on Ethanol fuels.. When I had my '74 Beetle, I ran 93 octane because it ran better and started hot easier
 

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I've never heard of premium gas not having ethanol. If it doesn't have ethanol, then the 87 at the same pump doesn't either. Ethanol is mixed with the gas at the refinery before the additives that make it have a higher octane are added. If you want ethanol free gas, go to a service station that sells it. The engines didn't run smoother on 93, that's in your head. No lawnmower on the planet that I am aware of will do any better on 93 than 87. These little engines are low compression engines so high octane is just a waste of money.

Matt, your reasoning makes no sense at all. The higher the octane, the MORE difficult it is to ignite the fuel. That's what octane is. If your engines were starting better hot with higher octane fuel then it sounds like you have a timing issue, not a fuel issue. If your timing is off then higher octane fuel might help but then its not a good thing to use high octane fuel, its use is simply and indication of a problem.

The only, or most common engines that require high octane fuels are in your high end vehicles. Some Mercedes Benz vehicles, some high performance cars like Vettes might require it, but then its not all of them as I know Vettes that do fine on 87. And the Mercedez Benz cars dont really require it, honestly. If you put the low octane fuel in it the knock sensor will detect possible knock issues and will retard the timing. That will reduce the power output of the engine. A modern computerized engine doesn't really require high octane fuel to run. It only requires high octane fuel for RATED HORSEPOWER.
 

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I am aware of the octane requirements of all my equipment and vehicles. None of them require 93 octane. The surging was not in my head. Now maybe the 87 I put in was bad? One thing I did notice is that at this Shell station the fuel pumps have a sticker that says "this fuel may contain ethenol" where as all the other stations I frequent say "fuel contains 10% ethenol".

Do some stations not use ethenol all the time?
 

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I'm fully aware of what octane is. It is more resistant to pre ignition, which is why it might run better on an air cooled engine.. My Beetle would pop and crack before it started hot on 87 octane, 93 octane still started it pretty hard but I think the ignition timing was pushed a little too far ( I never messed with it ). Engine was very strong and wasn't 100% stock. ACVW's aren't my specialty which is 1 reason I sent the car down the road to a new owner.

For the most part, vehicles made after 1973 are ok to run on 87 octane because the compression ratios dropped below 9:1 that year, and remained that low into the 80's.
As far as non ethanol in 93, a Station owner told me that some stations get fuel from 2 suppliers and the 93 might actually be ethanol free depending on the supplier which is where ~some~ comes in. Only what I was told by 1 person, can't verify it and a major brand station likely pumps E10 93 octane.. Most of what I tinker with is older vehicles. Tractors is a side thing for me.
 

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I am aware of the octane requirements of all my equipment and vehicles. None of them require 93 octane. The surging was not in my head. Now maybe the 87 I put in was bad? One thing I did notice is that at this Shell station the fuel pumps have a sticker that says "this fuel may contain ethenol" where as all the other stations I frequent say "fuel contains 10% ethenol".

Do some stations not use ethenol all the time?
As far as I know, there is no difference. Either the station uses fuel that is E10 or it uses ethanol free gas. They put "may contain ethanol" as it sounds better than "contains ethanol." So many people hate ethanol that it's losing popularity fast. Word got out that a small local station has ethanol free gas and its hard to find a pump there now, whereas before you were hard pressed to find a car there.
 

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Here in Ny, Ethanol is not used all the time. Most of the time It used to be summer blend contained ethanol but Winter blend did not. pumps were still marked 10% ethanol. I don't think that is the case anymore, but I just run what I can get, and to date, I have not had a problem due to Ethanol.
 

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Discussion Starter #8
Thanks guys. The next time I need fuel for the tractor I will try 87 octane again and see if the surging returns.

Has anyone tried one of those ethenol test kits?
 

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:howdy:As many folks have stated, there are many variables that could make a "low compression" engine seem to run better with 93 octane. And as was also stated, 93 octane is just lipstick to cover a flaw. But then, most of those "flaws" are very minor (glowing carbon deposit---advanced timing---lean fuel/air mix ect.ect). In THEORY, gasoline/ethanol mix will enter the combution chamber at a lower temp than straight gas, and have lower emissions, but thats THEORY! IF the gas/ethanol mix is at the correct proportions 10% or 85%, and your fuel system (seals, hoses, carb body, intake gaskets) can support it, go for it.
The problem was, in the mid-nineties when I drove the tractor trailer that delivered to the stations, it was the DRIVERS responcibility to do the math for the mix of ethanol to base gas as he was loading the trailer!
Back then, to get 87 octane we blended roughly 5 pints base gasoline, 1 pint ethanlol, and 2 pints of "drip gas" to get 1 gallon of 87 octane gas. If you blend 7 pints gasoline with 1 pint ethanol (roughly 10%) you get over 100 octain. Can't let the public know what a bargain that would be!!! so thats why it was cut with drip gas to get the lower octain. Drip gas is the liquid condesation from natural gas prodution that until ethanol came on the scene was burned off at the refinery to get rid of it---and we are now paying $3.50 a gal for it----hmmmmmmmmmm. It is technically gasoline, but has very low octain so it's perfect for cutting the blend.
Look for the tag on the pump. Fed law states the pump MUST be labeled showing that you are buying ethanol. OK, I'll shut up now.
 

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Just wanted to add to the last posters comments . I recently found out that in Maryland that some counties are mandated to sell only gas with ethanol and others are not , the ones that are mandated to sell gas with ethanol are required to have a decal or sticker on the pump disclosing what percentage of ethanol is in the gas . I guess each state has it's own regulations & mandates .

Mike
 

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As far as I know, there is no difference. Either the station uses fuel that is E10 or it uses ethanol free gas. They put "may contain ethanol" as it sounds better than "contains ethanol." So many people hate ethanol that it's losing popularity fast. Word got out that a small local station has ethanol free gas and its hard to find a pump there now, whereas before you were hard pressed to find a car there.

one thing i have noticed in my travels aroudn the midewest is mid octane rated gas has ethanol, while at the SAME pump the lowest octane and the highest octane do not. The low 85/87 octane gas actually costs more than the mid grade because it is ethanol free! but i've noticed my truck gets about 3mpg better mileage on 85/87 ethanol free than it does on 89 that contains ethanol.

we had 1 station in town that had no-ethanol gas, but they recently switched to 10% because they went with a new supplier that happens to own an ethanol plant in town.
 

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most 89 is blended at the pump, with a ratio of 87 and 93. Only stations with 3 seperate holding tanks for gasoline has non pump blended 89 octane.. If the station has 2 holding tanks, then they blend 89 at the pump.
 

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I'm sure this has been posted before but just in case:

http://pure-gas.org/

Its a list of stations that sell ethanol-free gasoline in the U.S. and Canada.

JK
 

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I'm sure this has been posted before but just in case:

http://pure-gas.org/

Its a list of stations that sell ethanol-free gasoline in the U.S. and Canada.

JK
Thanx for the link nobog!! It's interesting that here in Ohio most of the stations on the list are Marinas---boat use. Surprizing since alky burns cleaner than gas plus if you spill some, the alky will evaporate away but the petrol won't, leaveing dirty water.
That said, just as you use fewer gallons of diesel than gas to get the same heat (HORSEPOWER!) straight gasoline has more heat per liquid volume than alkyhol. Hense the higher the ration of alky to gas blend, the lower your gas milage number will be. Did you ever see the jets for a alky carburator then the gasoline jets for the same carb? I think you could drop a cat through the alky jets, no problem!!! It takes that much more liquid alky to make the same horsepower as gas. In racing apps the advantage is alky is much cooler entering the combustion chamber plus it attracts oxygen for combustion.
 

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Oh and I forgot, the octane rating for straight alky is sky high so you can build your engine accordingly with 14-15 to 1 compression and still have lots of ignition advance!:fing32:
 

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one thing i have noticed in my travels aroudn the midewest is mid octane rated gas has ethanol, while at the SAME pump the lowest octane and the highest octane do not. The low 85/87 octane gas actually costs more than the mid grade because it is ethanol free! but i've noticed my truck gets about 3mpg better mileage on 85/87 ethanol free than it does on 89 that contains ethanol.

we had 1 station in town that had no-ethanol gas, but they recently switched to 10% because they went with a new supplier that happens to own an ethanol plant in town.
That makes perfect sense.

Ethanol does not contain the same energy per gallon that gas does so your car will get worse gas mileage the more ethanol is in the gas. That's why everyone wants ethanol free gas, better mileage. Octane does nothing for gas mileage unless your car has a "premium fuel only" label on the dash. And you are going to pay more for gas without ethanol because the gov't is subsidizing ethanol production, so it's cheaper.

My car gets 10% better mileage with ethanol free gas. But I only pay 15 cents more per gallon. With the fuel at 3.30 a gallon, 10% would be 33 cents more. Well, I'm not paying 33 cents more so its cheaper for me to pay more for the gas that brings me further.
 

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Government subsidies for Ethanol have dried up. I think around January they ran out..
I drove by the station near my dads house on saturday on my way back from the car show and I noticed there big sign says " Ethanol Free Premium " right on it. It's a Fast Track station which is big in that area.. Probably sell a lot of premium that way..

I personally run 89 or 93 in my older cars, because the fuel quality is lower today than it was 30 years ago ( or even 15 years ago ). 1 reason is the Ethanol raises the octane, they lower it back down by using "drip gas" which is a byproduct of natural gas that used to be just burned off to get rid of it.. My truck just gets 87, and my '51 Chevy runs fine on it too ( 6.7:1 compression, it'll run on anything ) but I put 89 in that just because.
 
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