Gas/Oil Ratio

[Soundguy]

just curious why you are using 93 octane?

higher the octane.. the harder it is to ignite the mix. IMHO.. on small engines.. lower octane is easier to start.. may leave less intake deposits .. also.. oil addition to the fuel increases the octane on it's own..

just saying. i'm sure it won't hurt..

Yea, I never understood the market for them quart cans of pre-mix.:confused2:

For starters, a quart wouldnt even be two fill-ups on most of my saws. My SI saws and Newer 6400-7900 saws all hold around 28 oz of gas, so its actually not much more than 1 fill-up. Even my small 115 holds more than 18oz

Second thing is the price. Those would have to be well under $2 to even make sense. Since 2.5 gallons of mix cost me about 10 bucks for the gas (93 octane and ethanol free) and about $3 for the oil, thats $13 for 10 quarts of mix. No way would I pay $50 for the same amount in small containers.

 

[Soundguy]

I burn through too much fuel mix to use it, but Premix does have a Very Long self life and I keep a few on hand.

only way i'd use it is if I was loaning a mix fuel type implement to a buddy, and wanted to make sure he didn't burn it up with straight fuel. and normally.. i just hand them a 2.5g pre mixed fuel can anyway..

 

[tracter]

Fresh is Best , IMO

 

[LD1]

just curious why you are using 93 octane?

higher the octane.. the harder it is to ignite the mix. IMHO.. on small engines.. lower octane is easier to start.. may leave less intake deposits .. also.. oil addition to the fuel increases the octane on it's own..

just saying. i'm sure it won't hurt..

A few reasons I use premium.

True, it small engines do start easier on 87, but they also run hotter. In a small, screaming, air-cooled 2-stroke, I'll take the cooler burning gas.

Also, most of my saws have had the base-gasket yanked and are running a much tighter squish. In 4-stroke terms, this would mean that I increased the compression. Increased compression on what already calls for a higher octane. (most pro-grade saws are 89+)

And lastly, the place I buy fuel, 87 is e-10. Only the 93 octane at only this place have I verified to be ethanol free:thumbsup:

 

[Soundguy]

the ethanol free would have said it all for me..

and yeah.. if you upped the compression.. then higher octane is a benefit too.

as for cooling.. it would be the least of my concerns. it should cool adequately as designed with spec'd fuel.

 

[Paul N]

Oxygenated fuel is determined by each state individually. Here in Minnesota, I believe ethanol free is 91 octane. It may be different in your state.

 

[Soundguy]

in my county, only 1 single station has any non ethanol fuel.. it is one north of town and has a single 93oct pump non ethanol.

only other non ethanol sources are the airfield and marina.. both over an hour drive.. and charge 5$ a gallon almost..

 

[LD1]

as for cooling.. it would be the least of my concerns. it should cool adequately as designed with spec'd fuel.

Thats the thing, most of these upper-end pro saws actually do spec high octane fuel. I dont know about home-owner type saws though.

in my county, only 1 single station has any non ethanol fuel.. it is one north of town and has a single 93oct pump non ethanol.

only other non ethanol sources are the airfield and marina.. both over an hour drive.. and charge 5$ a gallon almost..

Sounds exactally like here. One little mom and pop type marathon has a single 93 oct pump that is ethanol free. And its only 5 minutes away

 

[Bluegill2]

I have two sources here for non-ethanol, both Conoco. Closest one 13 miles. Neither place advertises eth-free gas... If anyone here is from Missouri is looking, Conoco premium is ethanol free and 91 octane.

Most of my saws are ported, with compression bumped up and they run very well on this gas with Stihl Ultra or XP oil mixed 40:1.

 

[xyz123]

For the guy saying run the low octane. Read your manuals.

Stihl husky state 89 min and 89+, Solo 91 min, Dolmar dealer has a sign that says 89 min.

Running 87 in your stuff will created them to run hotter then need be.

Per Madsen's Octane Rating

The octane rating of a fuel relates to its ability to resist knocking. Knocking is the sound of the air/fuel mixture "exploding" inside a engine. Most everyone has run low grade gasoline in their car or truck at one time or another and heard a rattling sound come from under the hood. This knocking robs power from the engine and causes moments of extreme pressure on its internal components. It can also cause heat to build up. The same thing can happen to a pro saw engine, but you aren't likely to hear it knock. Cutting noise masks the sound of detonation. If you are running low octane fuel, you may not realize what is occurring until it is too late.