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Addicted To Tractors
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194 Posts
Discussion Starter #1
Hello guys I read on here that premium isnt good for the older lawn boys. is this true? i bought some 92 octane at the gas station and it said up to 10% ethonal. ethonal isnt my worrie but is the 92 too high of a octane? could it erode the floats in the carbs
 

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437 Posts
The 92 oct will not hurt an older LB motor but it might not run as well at it would on 87. LB'S relatively low compression and don't require higher octane. Higher octane actually slows down the burn speed of the fuel which compensates in higher compression engines and controls detonation. At 7:1 CR which I think most older Lawn Boy's are close to the 92 octane fuel will burn sluggish resulting in less available power. Noticeable??? That is questionable???
 

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The Sea of Green Machines
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4,767 Posts
It is too much money if nothing else. We already have to add the price of a can of oil to it.
 

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The Magnificent
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20,952 Posts
Octane and ethanol are two very distinct issues. In other words, increasing octane due to the presence of ethanol in the fuel is not necessary.

Also as noted, an engine will not necessarily run better on a higher octane than that for which it was designed. I think this is an urban legend started by Amoco in the 1960s.
 

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2 strokes forever!
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471 Posts
I use 87 octane in both of mine, no probs.....
 

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Lawn-Boys Everywhere
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1,292 Posts
Where I live, all gas has 10% ethanol added. In the county next to mine, the 87 octane gas has ethanol in it but the higher grades of gas do not. I've been using the higher octane, non-ethanol gas in my mowers forever and they run fine. Amsoil and some seafoam to every tank.

bruce...
 

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LAWN-BOY-AHOLIC
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1,349 Posts
I am a fan of ethanol in everything but my two cycles. Ethanol in your fuel mix can absorb water out of the air and then settle to the bottom of the tank or fuel container. When this happens the oil does not go with it, so you now have a mixture of alcohol and water without oil setting at the bottom of the fuel tank waiting for you to open the fuel valve and let it drain into the carb. If enough actual fuel is present and the engine starts and runs for more than a minute or two you could be running with little or no lubrication and you know how that goes. What to do if you live in an area with mandated ethanol? Keep your fuel mix container tightly capped at all times to prevent water in the air from entering the mix. Run the tank dry after mowing, or get a different fuel tank cap that has the vent hole plugged in it for use in storing the mower between use. Plastic wrap under the cap may seal the tank while in storage but must be available when you stop. Most of all shake the fuel container before you refuel and the mower tank before you start it up to help distribute the ethanol/water mix if it is present.

You can preform a test using a quart canning jar, some fuel mix with ethanol and some water. Fill the jar with about a pint of fuel mix add a couple of ounces of water, shake and then let it stand for a day or two. A oil less water alcohol mix will settle to the bottom. So if that happens and there is enough alcohol present for the engine to run, you will of effectively "Straight Gassed" you Lawn-Boy! LB carbs only hold an ounce or so of fuel so you won't need much "oiless" fuel mix to do the deed.
 

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Senior Tinkerer
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1,577 Posts
I am a fan of ethanol in everything but my two cycles. Ethanol in your fuel mix can absorb water out of the air and then settle to the bottom of the tank or fuel container. ...

Do you know to what extent the use of Stabil will help with this?
 

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Addicted To Tractors
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194 Posts
Discussion Starter #10
Ok thanks for all the help. I guess ill use this gas in my modified riding mower!
 

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Premium Member
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Amoco's urban legend of the sixties was their unleaded premium, they were the only ones who had it, AFAIK. I had a Ford Galaxie 7-Litre with a 427 in it that the PO ran exclusively on Amoco, and the valve guides and seats were completely worn out in 20K miles. His 0-60 runs in first gear probably didn't help it either.
 
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